First I'd not get a Brake Buddy.. I don't like a system that has to be installed EVERY TIME you tow.. I like to install it and "Forget it" as it were.
Now..... I have visited the "Towing Laws" web site and found errors. They seem to look for a law that specifically says "Car in tow needs brakes if"
However some states define a car in tow as a trailer
Finally.. Putting aux brakes on the towed car means less wear and tear on the far more expensive motor home braked, it means faster stops should you have to "Stand on the brakes" and it means you won't be seen as irresponsible when some jerk cuts you off so close you have no choice but to smack him in the ....ur... backside.
In short, cheap insurance.
Ready Brake (Surge brakes) under 500 dollars at the last web site I visited.
On, one other thing,, Heaven forbid what happened to me happens to you (Tow bar seperated from the rig) Car comes to one screatching halt with braking system and break-a-way.. Or runs through median head to head with the soon to be deceased without.
As I said... cheap insurance
Home is where I park it!