Hmmm...I worked with a classic-car-hauler buddy for awhile, and on occasion he'd pee in a 1-gallon plastic water bottle.
Like the ones for distilled or drinking water, which were also behind the seat.
When you're waking up in the truck, still beat-to-death-tired after several round trips to Pebble Beach, and you reach behind the seat where the water is...
This is exactly why I tell anyone that chews tobacco that they can chew in my truck but they better not leave their spit bottle in it when they get out.
