a friend of mine had an accident, traded his car in for a new one at the dealer.
a month later, after his original car was fixed by dealer they had the car up for sale. a guy he knew went to dealer and asked if the car's ever been in an accident, knowing it has. dealer (who actually handled the trade-in) said no, no accidents ever. i've also been to dealers that didn't know what they were talking about. i've been through 7 cars used and new.
that being said, i should revise my statement, dealers don't 'always' lie, it's just from personal experience and from what other people have experienced. Also they weren't from Ford dealers so i guess Ford dealers might be better. so revision, 'dealers are hard to trust from personal experience'.
private sellers lie / cover-up just as much as dealers, so I rather pay $1k less for the same car.