I would agree that if you have suspisions, they are probably deserved. Unfortunately, once they start it's hard to get the car out of the shop.

My last (and I mean my last as in never again) restoration had a similar story line. I thought about pulling the car 3 or 4 times but I was a little lazy. It was easier to keep things moving with the guy I was working with. In the end I regretted leaving the car there. Shortcuts were taken that weren't immediately obvious. In short, I got hosed and a great car that had no rust, only moderate collision damage was ruined by my standards. It is now impossible to turn back the clock and do the job correctly.

If you have doubts, stop the work and think about it.