The bumper guards were a good thing back in the day.
In my "younger" days I've saw many vehicles latched together due to someone getting a push start and one of the bumpers either went under, or over, the other one especially if they hit a "dip".
....anyone giving a push start would, at the last moment, ask "do the bumpers match". Did it a few times myself. LOL
Alvin, how I do push starts.