Increasingly it is becoming standard practice to have off site remote monitoring of a CCTV system, which means of course that police and other security agencies can be alerted when incidents are detected.
Sites can be monitored on a 24hour basis or outside normal working hours. On activity the monitoring station can issue verbal warnings stating the site is being monitored and if this fails to deter - keyholders, mobile guarding patrols or the police can be notified.