I've had Tires Plus (2 different shops in Minneapolis, about 5 years apart) strip studs on my car due to cross threading the things and running them on with an impact. One of those times I drove out of the lot, felt my wheel literally wobbling from being loose, and turned right back into the lot on the other side. Not sure how they parked the car without feeling it. Ont he upside, they kept the car overnight and repaired it and gave me a ride home, but of course it shouldn't have been needed to start with.
Ever since the 2nd event I've loaded up my wheels and brought them to better shops, even if it means I have to drop them off. I'm lucky enough to have 2 sets of wheels and a 2nd car to haul them in, so this may not be an option for you whatsoever. If it is, I highly recommend it. If not - I'm sure you'd be safe, I'm sure 90+% (maybe even 99+%) of the time the work is perfect, but having been burned twice I stopped going to them.