If you do not want people to put things like that on your land, simply, wall off your land and make sure the gates are closed. Anyways, what prevents them to put containers on your claim even without branding? Why would Jorb need to make an option to turn it off and on? Do you mean that you do not want people to put anything on your land in general? Because any other container with a lock is not different to a branded container. So yeah, erm... weird logic.
The host can rob anyone at any time on his/her claim. Frankly, that has never been an issue for the market that is being used by the majority of the trader population in hafen. So branding won't just benefit only us, but anyone else using the market. Actually, we do not need to brand our containers, since it is our own claim.
Moreover, the market is an example of a social project. It lets to see the flaws in the current mechanics and help to improve the game = any other social projects could benefit from the experience gained from the Sevillian setup.