Most rv connectors have a provision for running a extra 12vdc line from the rv to the toad which will eliminate the need for disconnecting the toad's battery. Also, it sounds like you're speaking of the legality of towing with or without aux toad brakes...ie; brake buddy.
The law differs from state to state with some not even having this law. Some are regulated to weight of toad, some are regulated to how far it takes you to stop from a certain speed.
The most important aspect is all about safety. It's a proven fact that in an emergency situation, you will stop quicker and in less distance if your toad is equipped with an aux braking system as oppose to not having one.
In addition you have to take into consideration that if you are traveling in a state that has this requirement and you are involved in an accident, you more than likely will not only receive a citation but also your insurance will refuse your claim.
So, it's your choice.'
Ron