Hold up the wrong placard or wear the wrong T-shirt at the latest medieval fancy dress parade and that is all it takes. You do not have to glue yourselft to railings, throw paint over shop windows or lob eggs at people, just being there and being "against" is now enough.
It is all geting very Chinese or North Korean in this increasingly dystopian land.
Just being there. even as a supporter, gets you a mug shot for the database; possibly for later use against you. 1984 is late, but it is here.