I've been out shopping for used vehicles the last few days, and after doing a CARFAX report on one of the vehicles I was most interested in, it turns out the odometer has been rolled back by about 100,000 km. What was surprising to me was that this was not a private seller or a generic used car lot -- it's at a Honda dealership.
What should I do? I still like the vehicle, and I'm tempted to let the dealer know and see if I can knock a big chunk off the price. CARFAX says the vehicle was sold at auction in Washington and imported to Canada, and I know how little vehicles sell for at auction because my uncle regularly attends, so I suspect the dealer's margin on this is huge and there's a lot of room to move. Other than the odometer rollback, the vehicle's accident history is clean.
On the other hand, the right thing to do would probably be to notify the police and Honda Canada.