I have done a few....
1. I won't leave my drivers license with the dealership or let them "photocopy" it for insurance reasons.
--- they have pulled my credit while I was on a test drive!
--- I have *often* see copies of other people's driver's licenses (blown up versions) lying carelessly on top of sales peoples desks, on chairs, in the trash cans!
--- One sales rep I shopped actually saved them and put notes on them! He told me, as he shoved a few aside, that he had to remember to call them back.
--- IDENTITY THEFT made easy!
2. I have a sales man go with me in the car (mainly because I won't hand over my license).
3. It came back ONCE that I did not do the shop. BULL!! As near as I can figure, the dealership disputed my report and since they couldn't find a copy of my driver's license on file, they claimed it never happened.
--- which leads me to wonder how they would be able to tell who the shopper is????
--- and any company that takes the client's word without asking me any questions is not worth working for! Seriously, how can you find out that the guy was retired business construction owner, with two kids in college, a brand new wife of eight months, with a new born due in two weeks? You just don't pick that stuff out of thin air!
--- the other possibility is that the MSC decided they couldn't turn in an accurate report that made the dealership look bad.
4. SOME MSC that have auto shops are GREAT to work with! Others, not so great. Regardless, be careful when you do the shops.