I've done quite a few, and generally they just confirm the info in their computer. I don't think I've ever been at the counter 15 minutes.
Had an oddball situation last time, though. Associate told me he had to call and verify my employment. Totally did not want that call to be placed, and luckily it was after 5 p.m., so I was able to believably say no one would be there to verify. Turned down for that one because of that. I'm doing another on Monday. I'll be interested to see if I hit the same snag!