Happened in NYC about 20 years ago. Registration in 1976 with the promise (politicians promises) that the lists would NEVER be used for confiscation.
Fast forward to 1991 corrupt left wing democrat mayor (sound familiar?) Dinkins rams confiscation of assault weapons through city council. 1993 NYPD confiscates all of those not certified as destroyed or turned in to police or sold out of state. NOTE NO police officers failed to carry out their unconstitutional orders.
Note that NO police officers were shot while carrying out their unconstitutional orders. Not so this time, if I read the mood correctly.