To help police departments trace cases of harrasment (which there were aplenty using unregistered SIMs).

I for one don't mind it so much, given the general inefficiency of the companies in question (they will probably have all the data going missing due to a flash flood before anyone gets a hand on it, and at least it's not as easy to mis-post 200k papers as a DVD ;). And of course, as AC said above .. fake documentation is all too easy to get by with.