Originally Posted by notinmybackyard

The upskirt pervert is a mentally a little boy doing something naughty. The trip is therefore 50% infantile curioisities about zizis and bumsies. The other 50% is the possibility that he will be caught.

As for the rest,
I do not advocate breaking a neck for non-consentual upskirt looking. But I think it would be ok to shove that cell phone/camera in their eye socket. Or perhaps break a finger or two to stop them clicking. It is less for the punishement of the perpetrator and more to send a message to other perverts considering doing the same.