Unless there are new Federal laws that I'm not aware of, the state in which the motorhome is licensed determines legal towing requirements. Other states can't impose the requirements for the vehicles licensed in their state on a vehicle passing through. We've never been stopped or questioned. 10 years, 100,000 miles
As to stopping faster. Faster than what? My Saturn weight about 2,500#. The fluids in the motorhome, i.e. waste water, grey water, fresh water, diesel fuel, propane, weigh more than that. That weight varies constantly. To the list of loads that vary; passengers, groceries, etc. Add those all up and the weight will well exceed the 2,500# towed Saturn.
The motor home weighs 25,000# +. Brakes were been designed to stop that weight given the tires friction and pavement condition. We now have two more variables;
brake condition and road surface condition. Do you see why their are lawyers?
What about when you need to stop fast and you slam the brake only to find out that the braking system won't allow wheels to stop turning? You can steer but not stop as fast you otherwise could. A decisions made by the Congress, and they know best.
Is the supplemental braking system on the towed vehicle working properly? How do you know in a real situation? Did you remember to connect it when hitching?
All the towed vehicle braking systems advertise in the magazines of the RV industry. Best not step on any toes.