What's the worst that can happen if I don't do a TM30?

FYI. Today, for the first time in six years of residence in Thailand, the immigration police came to look for me at home, took a picture of me with my partner and made her fill out a form, in Thai, that I had to sign jointly with her. I am surprised, frankly. I felt under investigation. At least fifteen Asian immigrants, unknown to the immigration police, have been living in my condo. I mean, I have nothing to hide or any reason to be afraid, I just wonder if paying two men to verify foreigners who are used to do the things according to the rules is not a waste of public money and a merely demagogic action. But that's it. I hope not to be out of topic, sorry.