I can't answer the part about Canada, but I do have experience both with groups identifying as CIRCA and, more generally, with clown blocs. I think the experience probably varies based on the make up (pun totally not intended, though I wish it was!) of the particular clown army or bloc. I also think it is one of those things that is better used as a tactic than as a group identification.
At least as far as where I am I have seen clown blocs be an effective way of throwing cops for a loop - they show up in riot gear ready to rumble and instead a bunch of clowns are running around engaging in hijinks, which really just makes the police look like the macho, violent bastards that they are. Recently there has been a group that always shows up to actions in clown face, and I find them shrill, predictable, and alienating.
