They don't even have to be drunk. And you don't even have to be in motion. I may have told this one before, hard to remember with the Halfheimer's and all, but I had a dude get within a genital-hair's width of walking in to the prop of a Mitsi, once upon a time. I'm looking at him, he's looking at me. He's walking back to chalk the mains and I'm rapidly going from "ah, upon which couch shall I pick my nose today?" to "Hey, dude, wtf, stop walking, NO SERIOUSLY". It turns out that there's no obvious and universally recognized hand-signal for "STOP MOVING YOU MUPPET". Some presumably more experienced ramp rat buttonholed him at the last second but I swear it was inches. I'd already killed the fuel, but he would have been deader than disco if he'd gone a step or two further. I actually had nightmares featuring various scenarios of what person-bits would be flung where.