You can get on secret watchlists by means of guilt by association, automagically.

https://legalclarity.org/what-happens-if-you-are-on-a-watchl...

https://abcnews.go.com/US/terrorist-watch-list-works/story?i...

https://www.businessinsider.com/how-to-be-on-fbi-watch-list-...

That also applies to just visiting absolutely harmless websites which have been deemed VERBOTEN! to visit, for whichever reason(again, in secret).

Have fun trying flying then, or being debanked. Would you like to spanked?