Had a friend loose his Chevy 1500 PU, in tow, behind his Class A. Towbar failed in some way. The breakaway system on the PU worked and he returned to find his truck "parked" safely on the shoulder of the interstate. I think maybe he did not have all the safety parts of the tow in use at the time but the brake system saved his truck, and maybe a big accident on the highway.
I have always had a brake system installed on my toad. This spring, on our return trip from SC to NY that brake system was malfunctioning. I proceded, with caution, and made it home without incident. I could certainly tell, feel, the difference in braking with that 4200 lb. tow behind me and my 26k+ Class A.
The problem has since been found and resolved.