Glowstick alarm.

[I-K-E]

not sure about that and the video is not exactly convincing but that could be down to the camera they are using

I guess this is something I should try out once I get some glow sticks (could be a while sodding car is eating my spare cash at the moment) and it's a simple enough system to try and if it works it could give early warning if your running patrols round a large area