Thinking more about weather sensors, which can also be thought of as cheap ($0-$20) 433.92 MHz low power battery operated beacons.

If I pick the sensor right, and if it's cheap / small / interesting enough, it could go into my backpack as an every day carry, and then if the backpack ever went astray there would a transmitter in it to help find it.

My #FlipperZero did decode a random #AmbientWeather #F007TH while I was on my bicycle, listening, so I have some proof it could work.