Originally Posted by redtop43

There's a nice device out there called Tile, which is a quasi-GPS tracker. Real GPS trackers are pricier and more importantly have very limited battery life. Tile connects to your phone by Bluetooth, and if you tap on your phone the appropriate tile will ring, if it's in Bluetooth range. It will also tell you the last time it "saw" the Tile, and most relevant to this incident, if anyone else with the Tile app on their phone comes within Bluetooth range of your Tile, it will update the location. So for example, suppose the person who took the wrong bag took an Uber and the driver had Tile on their phone, it would track the location to the dropoff point. I found this useful when I got on a flight, went to get my headphones, and they weren't there. Did I leave them in the hotel room? In the rental car? The tracker told me that they were in the Amex lounge, where I hadn't taken them out intentionally, but probably they slipped out of my bag while I was changing clothes in the restroom. I have one on my wallet, keys, TV remote, and both sets of headphones, and am going to add one to both my computer bag and carry-on. Also, if you press the button on a Tile, your phone will ring, so if you have your keys but can't find your phone, you can make your phone ring.

They're not overly pricey, around $15-20 each depending what model you get, and need an annual replacement battery which is about a buck.

They also make good gifts, since you can buy a multi-pack and give them out. It's not like each one in a set has any connection to the others. You can, say, give one to each family member to put on their keys.