I highly recommend having organized contingency plans.
Both because Tucson can be wildly leftist, and though they deny it, leftists are far more prone to instigating violent attacks; and also Sheriff Dupnick, who is such a panicky knucklehead that he may try to “bust them up”, either officially, or by trucking in SEIU thugs.
Some suggestions for prior planning:
1) Be aware of any vehicle avenues of approach near the assembly.
2) Watch out for undercover police trying to infiltrate and incriminate, even as “agents provocateurs”, asking inflammatory questions or making violent and threatening statements, looking for agreement. So it is very good to have people prepared to audio and video record suspicious characters. Both uniformed and undercover police will probably video and photograph you as well.
3) False flag infiltrators hoping to hold up signs or banners while being photographed, to discredit the group, or who want to start fights.
4) Definitely create a ROE handout for everyone. And since there will be friendly LEOs there, make sure that everyone knows to “let them handle it” first, because they are experts in confrontation.
5) While many people will have guns, it would be good for some to bring stun guns and pepper spray as well, so the group will have less than lethal options.
6) Identify cover in the area, as well as shade. Bring lots of bottled water, and some folding chairs for the older folks.
Right, and they showed that "expertise" in the situation with the marine which sparked this rally.
Honestly...