Mark, can you give us some more details on the perimeter alarm?
Here is a link to the Ford glossary web site... http://www.fordvehicles.com/help/glossary/?letter=a
The perimeter alarm consist of several hidden sensors within the cabin of the car. They detect air movement within the cabin and set of the alarm when there is a change in air movement.
The idea behind the alarm is that is somebody tries to smash the window there will be an air movement that will set of the alarm.
The systems are now well developed and are normally very reliable, as such false alarms are uncommon.
# Perimeter anti-theft alarm system
# Guards the vehicle’s doors, hood and trunk/lift gate. When an unauthorized entry occurs, the system trigger sand will:– Flash the head lamps, parking lamps and theft-indicator lamp on the instrument panel
# Sound the horn. Note: It will not be triggered by breaking glass or entry into the vehicle through a window. The perimeter anti-theft alarm system is designed to work with the factory-installed Remote Keyless Entry System.SecuriLock® passive anti-theft ignition system