Since I'm writing about a future scenario, such as under the authoritarian President De Santis administration, I quite obviously cannot provide proof. What I know is that laws and regulations should be scoped to preserve liberties under even the worst executive.

The many people who have SSSS on their boarding passes for 'extra scutiny' as part of some cryptic TSA process seem a good enough example of the Govt keeping secret lists of undesirables. A random selection of SSSS tweets:

https://twitter.com/mjs_DC/status/1097895615479144448?t=y2yY...

https://twitter.com/DoualyX/status/1029128870996324352?t=Jn9...

https://twitter.com/SheRoamsAbout/status/1056946018229669889...

Tell me these people are security threats.