I believed all of that until i read the last sentence. "uhh 911? a guest just rode tot with no seatbelt, can you send the police" lol "no we never checked his seatbelt..."
Some one would lose their job.
There are usually some sort of 'official' LEO on property to begin with - both in WDW and DL. That is who would be called. It would not go to emergency response (seeing as it is not an emergency).
I don't know about the trespassing charge though. Maybe willful endangerment or if they broke/cut the seatbelt then destruction of property. If they leave the ride vehicle, then sure, trespassing. But if you leave the ToT ride vehicle during the drop, then I suppose you have bigger problems on your hands.