I don't know how it is where you are but here in Britain the cops show up at your door and threaten to arrest you if you seem like the type of person who would organise a vigil after a cop kidnaps, rapes, and murders a young woman. Also they "warn" businesses hosting your anti-oil meetings that you might be a group of dangerous terrorists making illegal plans. They also ask social workers and nurses to let them know about people expressing sympathies for groups like Stop the War or the Campaign for Nuclear Disarmament.

Maybe you live in less of a police state though.