Originally Posted by Goodweed of the North
The thing won't blow up unless you purposely defeat the built in safety devices. But even with the safety devices, if you open the lid while the pot is under pressure, it could be catastrophic.
That's certainly true -- IF you could open the lid while the pot is under pressure.
Based on my experience with my two Kuhn Rikon pressure cookers and one other brand (can't recall the name), I'd say it's virtually impossible to remove the lid while there's any significant pressure in the pot. It would require near superhuman strength and a hearty dose of stupidity -- it's highly unlikely ever to happen unintentionally. That may not be true of older designs.