Man, I couldn't even guess how bizarre it would feel to suddenly be going for a ride like that.
My company runs barn doors on linehaul vans. I always check to see if anyone is standing around the dock door before pulling it. If I see a forklift or anyone standing around, I make sure they know I'm waiting by hooking up the glandhands and light cord.
Actually overheard a dock guy say he'd laugh if I pulled the trailer with the lift on it. I shouted up through the gap that it'd only happen if he kept screwing with the trailer after I got cleared by the supervisor to pull it. He went white as a sheet and walked away.