Most people ignore alarms and a club can quickly be bypassed by sawing thru the steering wheel.
Because onstar can be disabled by disconnecting the battery and my former car (2002 TA WS6) was stolen last August, I hid a gps tracker in my 2LT with it's own battery backup so I can track it if stolen. If I can get my hands on a service manual, I would like to add a hidden kill switch that disables the ignition when I'm away from the car by making the car think the auto. tran. lever is in "D", drive. That way I have prevention and recovery on my new camaro.