I picked up a nice Viscount Sebring for free. While going over it, I noticed the quick releases on the center pull brake were both open. The calipers had been adjusted to compensate. The bike didn't look like it had been ridden all that much, so odds are that it came that way from the shop.
Been in good bike shops, and been in bad ones. The more arrogant the mechanic, the more likely he's an idiot.