The point to remember is that there will remain thousands of unregulated drones/ model aircraft flyers out there, many flyers will not have heard of the schemes as yet and there hasn't been a great deal of publicity outside aviation circles. As of 30th Nov, it was reported that less than half of the estimated 120,000 model aircraft owner/flyers in UK had registered for the scheme. The ones who have a desire to cause a problem with a drone would be totally mentally bereft if they chose to register their drone first!
I suspect this legislation is going to be another dog licence / TV licence debacle because it will be almost impossible to fully enforce.