Dude wearing saggy pants = Can't move without using a hand to hold up his britches.
Dude wearing Lycra garments = Can run like the wind.Must kick off the pumps though.
BTW, the dude in SF who was arrested got hassled for refusing to comply with the direct commands of the Flight Crew. All he had to do was pull them up for the nice lady. He didn't and when someone won't do the minimum for a flight crew, you cannot depend on that passenger to comply in the extreme events. They are a risk to the rest of the passengers and should be removed.