This letter comes to us from Patricia, a mom do dedicated to fair auto repair she was willing to go to bat for her daughter. Here's what she says about her recent tire shop experience:

Hello Matthew,
I've got a question for you. I'm not sure where my daughter can go with this, but I thought I'd give you a shot! Ok, a brief explanation. My daughter has a brand new Dodge Nitro (about 3 months). After leaving her work one day last week, she noticed she had a flat tire. She walked to a nearby store and bought a can of Fix-a-Flat, which she has used on other vehicles that she's had. She used it, and drove the vehicle to a tire store to get the tire fixed. Without even looking at it, they told her she had to buy a brand new tire because she used the Fix-a-flat. This never happened before, and she told them so, in that same store. Their reply was that those kids were no longer working there. She didn't know what to do, and she had her two little children with her when this happened. So, she paid for that new tire.

I have two questions that I thought you may be able to answer, or at least tell me where I can find further information. The first one is .... Was this a true statement that these sales people gave about having to buy a new tire for using the Fix-a-Flat? And, how can you tell if a tire has been replaced or just fixed, when the tire is just about brand new to begin with? Please help. I was a working Mom once upon a time, and I get really ticked when I think that some of these unscrupulous bottom feeders get over somebody.
Thanks for your help!
Patricia C.

Patricia, you were 100% correct in suspecting some foul play here. A tire which has been temporarily repaired with a Fix-a-Flat type product can be plugged and used until it wears out. As long as the tire tech cleans the inside of the tire, there should never be a problem with it. That being said, you should always tell a tire shop that you used Fix-a-Flat on your tire. The gas that the product uses to fill your tire is nasty, so extra care needs to be taken when it's deflated. But replaced? I've never heard of this. I've also re-used plenty of tires that were repaired with Fix-a-Flat. I don't think I would return to this shop.