I think all trailers should have some sort of brakes on them regardless of how much the trailer itself weighs. Once you load the trailer down, you have all the weight of the trailer and whatever is on or in the trailer pushing you around. You'll save the brakes on your tow vehicle by having trailer brakes to help slow you down as well. I know most places if the trailer is 2k or more brakes are required. The lighter weight trailers probably need a way to either not hook them up or turn them off or something when the trailer isn't loaded or most likely you'll end up dragging the trailer every time you stop due to its light weight.
I wouldn't have tried towing anything with my B2, but that was just due to the horrible rear suspension....or lack of I think as bad as it was sagging without any load on it. However, one that is in good shape, I don't see why a person couldn't tow 3k with it using a equilizer/stabilizer hitch setup. Its the stopping problems that will kill you and get you into serious trouble. It doesn't matter if so and so cut you off...its your fault you ran into them because your vehicle was overloaded....hence the reason to have brakes on the trailer, it makes a huge difference sometimes.
I was coming home from Arizona several years ago on the freeway about 30 miles from home, had someone cut over in front of me from 3 lanes over to get to the exit lane, if it wasn't for the brakes on the travel trailer I would have used their POS car as a speed bump. You just never know when some idiot is going to pull out in front of you, or otherwise cut you off. They don't give a sh** they just have the mentality that they are invincible and they don't want to take 2 extra seconds because they don't want to get stuck behind someone pulling a trailer.
Trailer brakes and a good trailer hitch are going to be your best friend especially in such a small vehicle. A small fully loaded trailer can and will push the little bronco 2's around quite a bit, having a good trailer hitch with load leveling and stabilizer setup will help a lot. Adding trailer brakes to your trailer, or buying a trailer with them already is a wise choice with such a small tow vehicle.