OT, but I often leave unopened bottles of water in the car when I return it. I'll also sometimes leave one in the bus to the terminal or on some shelf in the (landslide) terminal for anyone who wants it rather than tossing them in the trash.

Some regions have many normal roads that are unpaved. Similarly, it might be necessary to take an unpaved road into a resort, to a park's entrance or parking lot, or to some tourist attraction, such as a small zoo or winery. It's common for overflow parking to be unpaved. Moreover, one can be driving on a major highway and come to a construction zone where cars are forced to follow some unpaved path. I've never thought of these situations as violating rental car contracts in the same way as taking the car along a tractor path or onto a beach or through sand dunes would forbidden.