I bought a aprts bike from a guy last year and he had a busa in the lot with 2 tenths of a mile on it. Kid bought it, wrung the throttle up and went over a parking lot curb stop into the side of the dealership...Bent the whole frame and put him in the ICU.
I've seen that before but it's a good reminder of why you don't let folks that "used to ride" borrow your bike