Yeah, it’d be a live monitoring footprint limited to, say, wherever you have/bring a personal device plus maybe wherever there’s a wifi network it knows. But you’d be able to see where the tag was when it last pinged you, so you could return to that location to search for it and get a more accurate location fix.
The only case my example doesn’t cover is if a third party moves the tag away from your typical footprint and networks.


















![XKCD #349 - "Success": [Four full-width panels arranged vertically, each with a label for number of hours elapsed, with a title above the stack of panels.]; Title: As a project wears on, standards for success slip lower and lower.; [Megan is standing behind Cueball, watching him as he sits at a desk working on a desktop computer on the desk.]; Label: 0 hours; Cueball: Okay, I should be able to dual-boot BSD soon.; [Cueball is on the floor fiddling with the open tower in front of him. Megan is not shown in the panel, but may be off-panel unless Cueball is talking to himself.]; Label: 6 hours; Cueball: I'll be happy if I can get the system working like it was when I started.; [Cueball is standing in front of the computer, which now has a laptop plugged into the tower. Megan is still not shown in the panel, but may be off-panel again.]; Label: 10 hours; Cueball: Well, the desktop's a lost cause, but I think I can fix the problems the laptop's developed.; [Cueball and Megan are swimming in the sea; an island and a beach can be seen in the distance.]; Label: 24 hours; Cueball: If we're lucky, the sharks will stay away until we reach shallow water.; Megan: If we make it back alive, you're never upgrading anything again.](https://lemmy.ml/api/v3/image_proxy?url=https%3A%2F%2Fimgs.xkcd.com%2Fcomics%2Fsuccess.png)

Yes: https://prosody.im/doc/turn
Further notes on implementing calling with XMPP: https://gist.github.com/iNPUTmice/a28c438d9bbf3f4a3d4c663ffaa224d9
…seems like things may have stagnated around group calling; for now probably need to consider something more video conferencing specific like jitsi or bigbluebutton.