I got a 100% agreement with majority too. I did not try to define anything formally, instead I judged each case by itself, asking whether I'd consider that thing a "vehicle". Which ended up meaning "car" in practice.

You only go mad if you try to lawyer things. Or your opponent does, which means that this test lacks the thing that really makes rules-making hard: determined opposition, would to trust your every word.

Good point! Although I'd do a somewhat different definition for people in the park. I'm not trying to recreate the entire legal and judicial framework.