[user104658]

Originally Posted by arista

Yes we will sell Temp Auto Sensors ($10)
if a bag is left.

Beep. Beep. DEEEE. Beep.

Problem Solved TS.

Do these exist?... That actually sounds like a pretty good idea. Something that goes around your wrist and then another part that goes on your bag, your wrist strap beeps if the bag is more than say 5 metres away for more than a few seconds. Let's sell them and become rich...