Take your bull horn.. comes in handy if they start chanting....
You need a permit for a parade, but if you have enough people you can join their parade, if the cops determine you would be blocking public access to the side walks. The main thing is that YOU have a right to counter protest, thank you Sam Adams.
No, we have laws here...and a bullhorn would require a sound permit. All we need to do to piss 'em off is to show up with a few FR members and watch the public stretch our ranks. Works every time.