Not arguing here on someones post. But,
Go find a long straight road, get up to speed, lets say 65mph. Do an emergency stop- put the truck into an antilock situation, lock the trailer tires into a skid, use your exhaust brake etc. See how far you go, try to do an evasive maneuver while doing this. Now do this with your trailer brakes unhooked, say due to a blowout that cuts the wiring or hydraulic lines. A 9000lb truck will have a real hard time stopping a 18000lb trailer. Say you leave the proper spacing between you and the vehicle in front, that space always fills up with smaller cars that don't care about their squish factor, do a panic stop now. The momentum of the rv will push you thru an intersection, down the hill, whatever is in front of you. I realize the engineers have made sure the brakes were up to the task, that the frame was strong enough, to move the load and stop the load under normal circumstances.
