If a march is surrounded: LINK ARMS!!!!!!
This is such a basic defensive thing that I'm surprised I have to write it here, but I don't see it going on at all during these demos. The Defenders of Exploitations were in "selective arrest" mode again yesterday, meaning they're just picking people out of the crowd at regular intervals for spectacularly violent arrest and/or pepper spraying. Their goal is to exert maximal violence against a manageable number of individuals (usually a handful at a time), and force everyone else to watch helplessly.
Next time a march is boxed in, LINK ARMS and sit down or scatter to another intersection immediately. Force them to haul in 300 people or no one at all.