Why don't they register all cell phones, and have them all regularly inspected by the police for kiddie porn, if they really want to solve this problem?

Personally, I'm rather tired of hearing about kiddie porn, but, I agree it's a problem. Why not simply have the police register all cell phones like they register handguns, and have them regularly inspected for kiddie porn? Surely, this would largely eliminate this problem. I suppose the perverts could simply use computers, and one could register these, as well. But, if kiddie porn is really as big a problem as the authorities say it is, and, if only truly dangerous perverts have this material on their cell phones, well, why not just shut this down? Of course, if the intention is just to intimidate, frighten and control the population as a whole, and if the vast majority of people actually have unwittingly downloaded kiddie porn from any number of apparently harmless sites without knowing it, then, I suppose that wouldn't work very well, would it?