Any pressure cooker is now considered an assault weapon and must be registered at your local Police dept, those with built in timers are subject to confiscation.
Same with assault box cutters with more than 1 extra blade in the handle.
Nails, ball bearings, glassware, fireworks, etc cannot be sold with a pressure cooker.
Sounds crazy but i would bet some nut job is thinking about this quite seriously right now.