Go for it. In VA at least it wouldnt do anything but result in the caller getting in trouble.
A complaint (which at least in VA is not anonymous) would trigger a law enforcement investagstion where they must find clear and convincing evidence of the person being a danger to themselves or others.
So your plan would result in a lot of false police reports (which is a crime) and a waste of LE time.
Ah, good counter plan, jail anyone who reports Democrats may be dangerous. Good luck proving whether or not someone subjectively feels someone presents a danger.
Hmm you may have a point. So how about we do this instead. Follow Democrats lead and pass other laws removing rights they may not like by using the absurd standard they may commit a crime at some unspecified date. By the way, being free is also a right.