The person riding the bicycle does those things, the bicycle is a tool. A tool can't follow rules.

You can take roller skates off, get out of a wheelchair, and get off a bicycle.

Imagine you were wearing roller skates being pulled by a dog.

Imagine you were sitting in a chair, with a roller skate bound to each leg of the chair, rolling down a hill.

Imagine you were a flea in a roller skate rolling down a hill.

Imagine you were a dog in a wheelchair rolling down a hill.

Imagine you were a flea on a dog in a chair with roller skates on its legs rolling down a hill.

> Roller skates are clearly not a vehicle

I don't think that's particularly clear and I think a non-negligible number of people would disagree

It isn't so clear to me. If it conveys a human in any way that humans don't naturally move unassisted then in my mind it qualifies as a conveyance and hence a vehicle, especially in the sense of the the French véhicule, from Latin vehiculum (“a carriage, conveyance”), from vehere (“to carry”)

Stilts? How tall? Platform shoes? How tall?