One of our readers in Minneapolis wrote to us about a new scam we had not run across before. Unfortunately she fell for it, and felt compelled to share her story with the Posse in hopes of keeping others from falling for it also.

Mary Jenkins had a knock at the door on a Saturday afternoon. A respectable-looking man with a clipboard introduced himself as a tree doctor hired by the city. He was in her neighborhood to inform residents that numerous oak trees in the area were afflicted with Oak Wilt, a fungus-related disease. He went on to say that this fungus was infectious and could quickly spread to other oaks.

This news concerned Mary. Her home had been been in her family for generations and her grandfather planted the Red Oak in the front yard many years ago. That tree provided shade for her family for years. The thought that it was infected dismayed her.

The man said he had already taken a look at the tree before he came to the door and hated to deliver the bad news, but her tree was indeed infected with the fungus. He said the city had instructed that any tree infected with Oak Wilt must be cut down immediately to contain the fungus and prevent an epidemic. Mary was shocked by the news, but sadly agreed to have her tree uprooted. What else could she do? The city required it. A crew came the following morning and cut down her Red Oak, hauled it away, and handed Mary a bill for the testing of the tree and the removal: $600. She paid with cash without a second thought.

Mary's neighbor visited a few days later to ask her about the oak. She knew how important the tree was to Mary and wondered why it had been removed. Mary retold the sad story and asked her neighbor if the oak in her backyard was also infected. Her neighbor said no tree doctor or city employee ever came to her home. At this, Mary became worried. She first tried calling the number on the bill she received from the crew that removed the tree, but the phone number had been disconnected. Then she called the city, who informed her that they had no information about Oak Wilt in the area, had not hired a tree doctor and did not order any trees removed.

Mary was devastated. She'd been had. Her historic tree, perfectly healthy, was now gone forever because she did not question the word of a respectable-looking man who claimed to be sent by the city. To add insult to injury, the crew that removed the tree damaged her sod when removing the stump and broke her gutter with falling branches. Mary had to hire a landscaper and roofer to fix the problems. All in all, the scam ended up costing Mary in excess of $1500.

To avoid this type of scam, take the following tips into consideration:

1. Call in a tree specialist and get a professional, independent "second" opinion.

2. Check with neighbors to see if they are having tree problems as well.

3. If someone comes to your door claiming to be sent by local government, call them to verify.

4. Never pay in cash.

5. Never allow someone to come do work on your home when you aren’t there to supervise.

It has happened again.

We get reports of this scam a dozen or more times a year: a crook posing as a utility worker comes knocking at your door insisting on being allowed to check your gas line or some other item. This latest email from a homeowner in Tampa got our attention because it demonstrates the boldness of these con artists and the risks homeowners place themselves in when they accept at face value the story of an insistent stranger.

Our homeowner, Megan, is wheelchair-bound and works at home so she was there when the front doorbell rang. She also receives regular deliveries from UPS so it was routine for her to expect someone at her door. This time though, it wasn?t UPS. It was a clean cut man wearing one of those generic uniforms common among service industry workers. The shirt even bore the name ?Ted?. But what added more credibility was that he sported a baseball cap with the name of the local cable TV provider.

"Ted" informed Megan that cable service was out in the neighborhood and that he was going house-to-house to identify the severity of the outage. He was polite and matter-of-fact. Megan noticed the handheld device that he appeared to be preoccupied with as he hit keys and studied the display. Her phone had also started to ring. In a hurry, she motioned to her TV as she spun around in her chair and returned to her office in the next room. The TV was in sight of her desk so she knew that she could keep an eye on "Ted". Meanwhile, the caller on the phone was irate and Megan was quickly distracted. As it turns out, the caller had the wrong number.

The scam only took a few minutes. It always does. When Megan returned, "Ted" was gone. She closed the front door and then thought to check her TV. No problems there. Crystal clear. She then glanced up and her heart sank?missing from the wall: six of her husband?s most prized baseball cards which had been beautifully mounted in a box frame. They were worth thousands of dollars.

Gone. Stolen.

Her attempts to locate "Ted" were fruitless. The cable company assured her they had no one by that name working in her neighborhood, nor were there any service outages reported requiring attention. And it turns out the irate caller was likely in on the scam. The call was traced back to a pay phone. The phone call was meant to distract Megan while the thief went to work.

How the thief knew about the collectible baseball cards is open to speculation. However, Megan's husband had recently attended a local gathering for collectors and she knew he was proud of his collection, often boasting about it.

A couple of facts to consider: Public utilities do not need to come into your home to test for neighborhood service issues. They have ways to make those tests outside. In rare cases (a broken water main, or a gas leak, for examples) you can expect the local fire department or even law enforcement to accompany utility crews.

At a minimum, here's what you should do in a situation like this:

1. Be clear on who the person works for and ask for identification. 2. Note the person's full name. 3. Inform the person that you will call the company and verify the information before allowing them in. Make sure to look up the phone number yourself. 4. It is not your problem if the person is insistent or impatient. A legitimate utility worker knows the routine and will wait. 5. If you need to, close the door--even lock it--while you make your call.

A bold con artist like "Ted" will try to talk his way around all of this. A lesser one will make a hasty retreat. You should report the incident to the police as quickly as possible to protect others in your neighborhood from becoming victims.

A homeowner in a small Georgia town recently told me the story of his botched roof repair. His indignation was in the contractor's shoddy work and the damage it caused to his home. But as I listened to him, I realized he bore responsibility for much of his current troubles.

A spring thunderstorm toppled a tree on to his house causing $60k in damage. The contractor caused further damage by failing to properly protect the home from additional bad weather while doing his repairs. What went wrong? The homeowner didn't hire a licensed contractor, didn't ask for references and didn’t stage payments to match work performed. The contractor began work right away and kept busy for a week. Because the homeowner could see the debris being removed and new roof trusses going up, he didn't hesitate when the contractor said he needed a check for $40k to buy the remaining construction materials and supplies.

Big mistake. That was on a Friday. By Monday the contractor was long gone. Repeated calls from the homeowner went unanswered and within a few days the number was disconnected. To compound matters, it was the only method of contact the homeowner had. The form containing the contractor's estimate included his name and phone number but no street address. The homeowner hadn't bothered to notice beforehand.

Another spring storm later that day poured water through the unfinished roof and brought down large chunks of sheet rock. Furnishings and carpet were soaked.

In defense of the homeowner, thunderstorms are a regular summer event in his part of the country and he was trying to get repairs made quickly. He contacted other contractors but they were busy repairing other storm damaged homes. Several offered to send out crews to tack up tarps until they could begin work.

You can learn lessons from this homeowner next time you have to work with a contractor for an emergency repair or any kind of work on your home:

1. Get references or use a web service that prescreens contractors such as BestContractors.com.

2. Get a written estimate on company stationary that includes complete contact information including a physical address that you have verified.

3. Never pay in cash or all at once up front. A reputable contractor has a line of credit to purchase building materials and pay his crew without needing a check from you.

4. Work only with a contractor licensed to do the work you require.

Spring time is also the height of scam season, especially for outdoor projects. Adding a pool in time for the Fourth of July is a popular project right about now and scam artists are waiting in the wings to rip you off. A recent spate of headlines about pool scams got me to thinking about the misdeeds of miscreants who strike a neighborhood by signing up a number of homeowners. The "Joneses Effect" plays a big part in the appeal.

Unfortunately, homeowners rarely invest as much time into thinking about how they will use a pool as they do daydreaming about lounging around one. Adding a pool to your yard should never be an impulse buy. Reputable pool contractors, like most contractors, rarely go door-to-door soliciting business. They don't need to because their good reputations keep them steadily supplied with clients.

So, if you've always been dreaming about a pool, wake up and do your homework. Make a list of how you'll be using the pool: swim laps, water sports, or just for playing in. Next, understand what type of pool you need and that your yard will support. If your yard has a considerable grade an in-ground pool may require the building of a retaining wall while an above-ground pool will require a deck.

Once you are ready to start, there are a few things you should do to ensure you work only with legitimate pool contractors:

1. Get three bids and compare them. Insist that they be detailed and each phase of construction is itemized. Also, bids should list materials being used. You can learn a lot by studying why one contractor specifies a better grade of aggregate when the others don't. Throw out any low-ball bid for what it is: trouble. The contractor is either dishonest or incompetent.

2. Query contractors on what types of soil evaluations they will do. If you live in an area with active ground movement you will want to pay close attention to this before beginning an in-ground pool. Contractors should also understand local zoning regulations and, if your home is within a covenant-controlled development, you will want to check with your HOA before work starts.

3. Before signing anything make sure to check out the contractor's license and certificate of insurance. Go online to the BBB and research the company for any complaints. If the contractor resists showing you his license it probably means he hasn't got one. And if the BBB report doesn't look good thank yourself for your diligence and move on to another contractor. The contract must include a completion date and a penalty to be paid to you when that completion date isn't met.

4. Now about money: I recommend you make your own arrangements for financing. I've heard too many hard luck stories from homeowners who were taken advantage of by high pressure lenders charging exorbitant rates and penalties. Never pay the full cost for the pool up front. Negotiate to keep your down payment as low as possible--ideally between five and 10 percent. Never pay in cash. Make this clear before signing.

5. My fifth and final tip: read and understand all warranties before turning over a dime. I know it is a pain to read all that legal goop but if you don't you could find yourself in the same mess as another homeowner I know. A week after his pool was completed and filled it sprung a leak--more like a sinkhole. Because that possibility wasn't covered by a warranty, it cost this homeowner thousands to repair.