You would not be arrested. At most you would be cited. It’s also on public lands where there is existing precedent for fining for something along the lines of trespassing.
This is instead on private property and probably protected under free assembly.
It’s been interpreted much more broadly than that to expand to freedom of association which has been applied to labor rights for many decades.
In this case, if it were to go toward the interpretation as protest, it might actually not be that unreasonable. Musk in many ways views it as protest afaict.
This is instead on private property and probably protected under free assembly.