And this is the problem. Anything that is done will only make parents feel safer. The predators will still be around, but will just go somewhere else. Every theme park, every playground, anywhere children gather could be closed, but there would still be predators because we (as a society) haven't figured out how to identify and stop them before they act - without, in effect, punishing someone for a crime he/she hasn't committed yet. Background checks and fingerprinting only identify people who have been caught.
But there are still people who will say " If it saves just one child..."