Set up Nativity scenes.
No, I'm not kidding. Real ones, not satires, and not with protesters sitting in for the religious figures.
This would serve as a visual reminder to the right that the savior many of them claim to worship was born into poverty, and that the wisest men in the world saw fit to lay gifts at his feet.
Great visual for the press, and a bad PR move for any authority that tries to take it down.
You don't have to believe in the story for this to have an impact. The undeniable lesson of the myth is far more important that the historical veracity of the event.
Warning: this must only be attempted with the most obvious and visible respect, or it will backfire. I would not try it without clergy present to be interviewed and photographed.
That's my quick idea. I have limited first hand knowledge of any encampment, so I realize that this is armchair advise. However, capturing and owning universally recognized images (such as the flag) is a time-honored part of any political movement, and this may be a good chance to do it. I wish I had suggested it earlier.
There will be more opportunities to attempt similar thing on national and religious holidays in the future. I think it's worth looking for them.
