Any registration list can be used adversely against you, if the political winds blow in a different direction.
The DoD sent me to Combat Engineering School, to learn how to perform demolitions. This benefited the Government to have people trained in battlefield use of explosives. But, it got me put on a registry of "potentially dangerous people on a plane". The 4-S (SSSS) category requires the strictest search and examination when boarding a plane. It is normally used for people who are suspected of nefarious things. It can be randomly encountered by most people from time to time.
Some states, like Hawaii very strictly read the "less than 750 Watt motors" on eBikes. If a person registered their bike, and it had a 750 Watt motor on the bike, Hawaii would find they are in violation of rule. They would potentially face fines and penalties for using what they thought was a legal bike. (Hawaii strictly enforces "no more than 749 watts" in their interpretation). Other states are pushing for an eBike driver's license as well as accident insurance. If people in those states are registered, and not insured, it could result in a state fine sent by mail for being uninsured should they pass that law.
For those who have motors over 750 watts, they could be targeted in more "reasonable states" which currently don't care.
Right now, most states just "wink" at 1-2kw bikes, as long as the rider is riding in a reasonable fashion. But, if things shift, they can find themselves on the wrong side of the law. They could discover they can no longer use the bike they paid good money for (banned from streets, banned from all but "motorcycle trails").
Signing up for, or being ON any registry creates the potential for future expenses and challenges should laws get enhanced. This is why so many people prefer not to register any "thing" they own legally.
These new restrictions/fines/fees are almost always done under the guise of "public safety".
