so after 2 years on inactivity they can send you a notice, after which you have 4 years to otherwise respond/update registration... a 6 year window is pretty wide.
whether one thinks this law is "good" or "bad" is a different question, but i dont really see a cons utional issue with it. my main concern is there should be some safeguards to make sure they send more than one notice, or ensure that they have the correct address. would suck for somebody not to receive it due to having moved or not received the mail, and not realizing they had this notice issued.