They require as many as 25 police cruisers and a helicopter to control...
4 - 5 snipers could do a pretty good job.
The time is coming when someone on the ground is going to shoot down a helicopter. Then, look out everybody.
Yup. Mossad-style, using a suppressed .22 rifle. Pick out the leaders (preferably ones wearing light-colored shirts that will show the blood) and put them on the ground, silently. The rest of the crowd suddenly finds better things to do elsewhere.