Guess what? People already do that.

ride them around for fun

Imagine the horror!

Thanks for pointing out how insane and disconnected the elon glazers are in believing their Teslas will drive off while they sleep to earn any kind of positive cash flow, then show up back home just in time to recharge for the commute to work, smelling fresh as a daisy.

I don't see a problem with the second one. The bus is already doing the route, it costs basically nothing to have a few joy riders.

People are going to take a shit in them.

Sure, somebody will. But the system will take note of that person, and then they don't get to ride again. Or they have to pay a fine. Or whatever.