I know. It shouldn't happen, but they take advantage of women all the time. I am the guy at work who has all of my female co workers come ask me if what they are being told is correct. I have a sick sense of humor so I like to take them with me in my car at lunch to the shop. I act like a typical guy who doesn't really know much about cars and just ask questions about what they are doing or telling my female friend needs to be done. Once I have given them enough rope to hang themselves with I let them know I used to work on cars for a paycheck, still do it for a hobby, and most of my friends are still mechanics. The look on their faces is usually priceless. They also suddenly have a different story about what needs to be repaired. Most of the time my friends tell them they are not working on their car and to give them the keys. I like to think that it teaches these guys a lesson, but I doubt it only does for a week at best. These instances aren't as frequent as they used to be. Most of my co workers have started taking their cars to my friends for repairs because they know my friends will be honest and do the repair right.
As for Bill Boosts point, its true. When I used to work on cars, we used to see it. It was the reason we would refuse to work on cars with over 80,000 miles unless we had worked on it before and knew the customer. Otherwise, with that kind of miles, things do break. It happens and can happen while you are repairing something else and then you are suddenly blamed. We would have people blame us for the A/C system failing 2 months after we performed a brake job. We would look at it and the compressor was just toast. It happens (esp in Texas where its hot). We were nowhere near it. Customers would blame us for their transmission failing after we replaced the alternator, etc. It was ridiculous. People like that are why shops often ignore legitimate complaints until you can prove to them how they caused the problem. There are just too many people out there looking for free work and it forces shops to treat everyone like a scam artist.