I had a front row seat to a trailer disconnecting. This was a trailer that was cut down somewhat from a tractor-trailer body and was heavy with equipment. I was following it into a small town and a light rain was falling. The tongue jack failed and dropped down to the road surface, then a small bump jacked the coupler off the ball followed by the safety chains failing. The trailer had no functioning e-brake and the skid plate on the bottom of the jack skated on the wet road doing next to nothing to slow the trailer. It traveled more than a block and scared the he!! out of several oncoming motorists plus a guy on a bicycle. The trailer crossed the oncoming lane and side-swiped a pole sending down a shower of sparks, but that only slowed it a bit. In this case, brakes would have shortened the distance but the damage was minimal due to a lot of luck. It was unbelievable how far that thing traveled before coming to rest and looking like it was parked at the curb in front of a small shopping center.