Yep, it's not a fast way to do it. I used to do it when I was a teenager and was grounded while my parents were out of town. Drive around while they're gone, and then rollback the odo before they get home.
no those particular trucks are the ones that have rolled over back to 0 and started counting again. twice. maybe three times. nobody remembers. ive worked on old junk semis like that, and they still are probably still going now. one truck I worked on had 1,600,000 km on it, the odometer had an extra digit on it to count the millions.