I witnessed one go up a few years ago (although it was being used by hospitality and not carrying any cars) same situation, burned to the ground after they dropped the trailer to save the tractor. All the propane for the kitchen made for quite a spectacular fire at 4am.
Keep in mind these trailers will have their own fuel tanks (or propane) to run the genset and AC units, not to mention any welding supplies, gas cans for scooters/golfcarts/etc plus gas left in the tanks of any other motorized vehicles that are being moved.