Sorry if this is a re-post or in the wrong place.
I’d never of thought of doing that, fair play to the driver - I bet he was giggling all day 
I had a similar experience some years ago. i was delivering to Asda in beckton late one night, not the nicest of places to be, when i arrived, about 11 pm there was already a truck in the yard unloading, so I pulled onto the drive leading to the doors and waited. there had been one or two problems with drivers being abused or where someone had tried to open the rear doors to nick stuff out, so we were told to lock our cabs, and if anything happened to sound our horn to alert the store staff, and phone 999.
on this particular night, a drunk staggered across in front of me, and made his way rather ackwardly down the side of the truck. about half way along, he dropped his keys. as he trid to bend down to pick them up, he over balanced and staggered forward past them, turned around, bent down again, and agin staggered forward past them. Then he noticed this big truck next to him, so, taking his time, he reached out an arm to steady himself on the side of the truck…missed it completely, and fell underneath the trailer! by now i am in stitches, as all i can see are two legs sticking out from under my trailer.
Eventually he manages to pick himself up again, and this time he reaches out slowly, makes contact with the trailer, then starts to bend down to reach his keys. about this itme, i place my foot on the brake and release the parking brake, which emits a loud hissing sound of air escaping from the trailer, this shocks the drunk so much, his pushes himself away from the trailer, staggers a good ten feet sideways, before falling in a heap on the grass!
This time he just gives up, crawls on his hands and knees, picks up his keys, and crawls off to the bus stop, where he picks himself up!
pmsl, how come nothing funny ever happens for me to see!?