I don't know about elsewhere in the country, but around here the malls are central to different gang turfs. The malls or at least a portion of them are considered to be common ground, but the parking lots and the out parcels are not and may belong to one gang or another. Around here the Sheriff's Department have erected security towers in the parking lots to try and control gang activity. If you are looking to get mugged, raped, beaten up, car jacked, or otherwise accosted, just go to the mall. This mob storming of theaters has happen here in Jacksonville several times. Mall managers are likely afraid of the gangs and retaliation for acts that limit or control their behavior.
The last time this happened here, the police surrounded the entire Mall and corralled all the little knot heads, arrested them, and held them until a parent came to claim them. The word was that next time there would be big fines to pay before they were released. So far, we haven't had another incident.