As far as I know they do need to get a waiver signed to show the episode.. BUT, most of the people you mentioned wouldnt know they were being complete dumbasses, and wouldnt care..
You'll notice on some COPs eposides that the suspect's face or other's faces are blurred out.. That means that they couldnt get a waiver from them.
Throw $50 in someone's face and they'll let you show them doing ANYTHING.. Ever tune into Funniest home videos?