I doubt there will be much of a turn out. Phoenix metro has a long history of not caring, and certainly not protesting, except for a very limited number of leftist hot heads and illegal immigrants.
However, I also expect that those who do attend will be carrying guns, and may likely outnumber those who aren’t.
Plus, the Phoenix PD will be all over the place, and “Them fellers know how to shoot.”
If you want to catch rats, you have to bait traps.