On the fact of it a crazy idea. Another case of loony policing/government.
But when you look at what they are saying perhaps not so ridiculous after all. They are not looking for 4 year old terrorists, but children being taught to hate by adults in or out of school. Another form of abuse that is apparently going on in some Muslim communities.
I still think it's wrong. It won't work properly and for little or no gain will cause more bad feeling in the vast majority of Muslims who are not part of the problem.
I think we should be approaching this from a different direction. If we're openly admitting that there is a problem at last then we should be dealing with it more directly.Once you start down that line, then ALL forms of religious teaching is indoctrination, i.e. brainwashing, because if you catch them young enough they will believe whatever you tell them. And while stopping the teaching of unsubstantiated, ludicrous and wishful belief systems to vulnerable children is desireable, it ain't gonna happen. There was an occurrence recently of a child from a Christian family insulting another child at school saying that she was going to hell because she didn't believe in Jesus as saviour. The parents of the victim and the school head were outraged, but the parents of the bully were mystified as to what was wrong with that because the same indoctrination was already instilled in them. They'd just passed it on because they believed it to be true.