I just picked my camper last week, and it has brakes on it. I got the wiring done before I picked it up, just to be done and over with it. While I was at the place installing the wiring, I overheard the owner tell a couple that if the trailer has brakes, they must, by law, be operational. I don't know if he was just trying to sell to them and make them buy a wiring package or not, but he also told them that they could sell them a converter from a 4 wire to 7 wire so they can have brake lights, turn signals, and running lights on the trailer, but no brakes.
So check the laws where you are. Easiest way is to just contact the State Police. They should know this kind of information. But I would recommend getting the wiring and controller at some time. This is the first camper I had with brakes, and once I got the controller adjusted, it made a huge difference.