This thing sounds like the sort of thing done to "get 'er done", to not spend lots of billable hours that a homeowner isn't gonna want to pay for, and to not look like the electrician was gouging the homeowner, but still look like he fixed the problem. "What, ten hours at $X an hour to find and fix a loose screw on an outlet?!". And if a subsequent problem arises from this bad fix, the electrician could claim that "I didn't do it" and someone else was messing around before or after he was there. This is a shoddy way to do business, I'd agree.