> What happens when the commuter I pick up vomits in my car?

You clean it up and make a decision about whether you'd pick them up again.

> Or steals something from my car?

You call the police and tell them who that person is and where they live.

> What happens if I get picked up by a person who changes their mind about where they're going?

You tell them to drop you off and you don't ride with them again.

> Or decide to take an unplanned detour to go to the store

If you're fine with it, you go along with it. If you're not find with it, see above.

> or back home to grab the laptop they forgot

See above.

> or to score some heroin?

If you like heroin, ask them to pick you some up too. If not, see above.

> What happens when the driver gropes me?

Get out, report them to the police, don't ride with them again.

> Or I grope the driver?

Please don't do that.

Is it really Waze's job to resolve these issues beyond blacklisting users?