[ghaff]

I've never tried to take a rental truly off-road but I've definitely had them on very unpaved roads they probably shouldn't have been on. You can get true off-road vehicles in locales like Death Valley but they're very pricey compared to a standard rental.

[bombcar]

Drive it like a rental and don't destroy it, and you get away with murder.

A lot of the "don't do this" rules on a rental are just so they can stick your insurance with the cost if you break it.

In reality, if the damage is very slight and the person checking them in doesn't want to do the paperwork, it's going to slide.

If you do drive off-road in a rental, wash it before returning it.

[ghaff]

I've definitely had a number of minor scrapes etc. over decades and I've never once had an issue--though I've almost exclusively dealt with the larger companies for whom minor scrapes etc. are presumably considered normal.