That's as maybe, but it is the law of the land and Immigration are allowed to enforce it.
The farang is the one in front of them, and the farang is the one that has to provide proof of residence, whether its up to them to do the registration or not. I nearly had a 1 year Retirement Extension bounced 2 years ago for lack of TM30 receipt in passport ( I was recorded in their system, had lived in the same house for 14 years, but didn't have the receipt).