What's the permit for leaving your product lying on the public sidewalk? There are several (for signs, seats, etc), and you're also supposed to pick up after your animals, not leave stuff laying about.

Undocked transportation? I think that without some formal approval it would be within the cities right to confiscate items left on the public right-of-way and auction it off to the highest bidder.

You can't even legally leave garbage out for collection (in unapproved containers) except for certain days.