Possibly.
But the "occupiers" may look on this as equivalent to tree sitting, and dig in.
On the positive side, McDonald's may get tired of supplying a MacBathroom for the whole crowd. That could have a dispersant effect.
McDonalds might not have a problem with this. I have a pretty good idea that these dopes are not just ducking into Micky D's for a potty break. They are not all vegans and I rather doubt most of them are sustaining nourishment from Wheat Germ and Carrot salads. Something tells me that quite a few Double Quarter Pounders with Cheese are being sold to them.
A good old fashioned cold rainstorm should do the trick.