The law is still on the books, but I don't think it is enforced anymore--

When on US Forest land you were required to have a shovel, axe and bucket in the summer for fire suppression. They used to ticket you if your group didn't have it.
Didn't matter if you were on foot, motorcycle or car.

If i wasn't such a bleeding heart libertarian, I would like a similar law for other needed emergency gear based on environs, (avi gear in avi terrain, water in the desert, etc.)