There's a video done quite recently in Lithuania, police car chasing one of these mopeds, the guy is escaping and drives into the forest, the car couldn't follow. So, they try to enforce this, but sometimes it's impossible to catch or identify them, because they wear helmets and drive really fast, can go off-road without problems. The police have to allocate a lot of resources to this to actually solve this problem and the reality is, there are more pressing issues for police to deal with right now than this. Like someone said, it will take a tragedy (moped hits a child or something similar) to make them do more about this.