Suppose K-Mart calls the cops to clear their lot. Sonic doesn't have the same view as K-Mart. They actually like people on their lot. Do the police then have the right to arrest people from the Sonic lot? I don't think so because the police don't have a complaint from Sonic.
If the police dragged people from one lot to another so they could make the arrest, then that would make for a very interesting court case.
As I understand it, Sonic did not allow the cars on their lot to be towed. That tells me they weren't a party to the complaint. Of course, I suspect I will be corrected by some of the new homeland security volunteers very shortly.
Bad assumption. Remember, 400 people were involved, that's why they were gathered in one place.