Trackers The Bad Side

Hey ho! Suppose it had to happen, you know those cheap(cost wise) easily bought trackers you can get? Well someone posted on a tomcc site that they found a tracker on their bike, they didn't put one on themselves! It's a new trend for theiving twats to go around the popular biking haunts see a bike they like slap a tracker on and go pick it up later at their leisure!! I wonder if they will make a scanner to detect trackers??