Perhaps they technically are supposed to wait 10 minutes, but I've seen them be in and out in less than 5. Back when I was working as a doorman in Dublin, a co-worker at the bar showed up and parked in front, just to run in to tell the boss he was there and that he'd be back after he parke in a proper spot. He'd even asked me to keep an eye for clampers, and tell them that he'd be back in a minute to move the car. I swear to you, 2 minutes later, I popped into the bar to deliver a message to the manager, came out 90 seconds later, and there was a clamp on the car! So all of it happened in under 5, so they disregarded the rules if they are supposed to wait at least 10 minutes.
As for clamping the clampers, that would be absolutely fantastic revenge, and I'd pay money to see it being done!