What are you going on about? Can kids go into bars and be around beer? No. If they are, the owner is charged.
Make them apply for a license, have it in a designated area and only allow adults to access it. I'm not into the half naked B.S either and there should be indecency charges laid where applicable.
If it is really about protecting kids than just ban them from the event. Why would anyone bring their kids to such an event anyways? Maybe the parents should be charged.
I can tell you the Toronto parade is one of the largest in the world and it helps our economy.