Are guesthouses in Thailand required to register all guests with immigration authorities?

We (husband and I ) are on the road touring the MHS loop staying at varies guesthouses for three nights or so. I notice some guesthouses only make photocopy of my passport and not my husband’s.

Are the guesthouses supposed to register all guests and relate the info to immigration?

I read someone got fine because her landlord did not fill out the form for her or something.

We are US passport holders on Setv+30 days extension. We stayed the first two months + in the same condo in Chiangmai.

We want to do everything in accordance with the law so we don’t run into problems down the road. We already plan to come back in the future before we even leave the country.

Thanks.