We had a Growler and Non-starter system fitted in our van back in April. A couple of weeks ago whilst sitting in the van in Exeter services the alarm went off. Slight panic ensured as we hadn't set it but eventually all settled down and peace and quiet returned. Then messages popped up on my mobile saying there had been a jamming attempt detected. To cut a long story short, we sent an email to Eddie (fount of all knowledge at Vanbitz) who explained that the system had detected something it didn't like such as an attempt to block its communication with the local GSM mast so it put out a warning and let me know. Thinking about it later I did recall seeing some shifty looking characters lurking around so pleased the system was on the ball!