A 10-Year Battery for AirTag

I know this is useful (for something), but I'm stuck on the plot holes in the motivating story...

Why didn't they replace the battery when the app complained?

How long would a thief really keep the AirTag anyway?

If the thief did keep the AirTag and you tracked them down, then what? A confrontation has a fairly high chance to have a worse result than losing some equipment. You could try to get the police to do it, but that's going to take more time, during which the thief is even more likely to ditch the AirTag.

Anyway, you're really swimming upstream trying to think of aigtags as an antitheft device. They're really for something lost, not stolen. Generally, they are specifically designed to not work well in adversarial situations.

I've retrieved stolen bikes, one because of an airtag. Showed up with a couple friends standing by but not trying to be intimidating. It's mostly about staying calm and telling the person this is mine, I'm taking it. They always say "no it's my friend's, you're gonna piss him off" or "I just bought this" or something. Maybe you offer some fraction of a "reward" to smooth it along and cut your losses. Don't try to start a fight and it generally goes OK. Also, try not to accuse them of stealing, they'll just get defensive. "It's someone else who is screwing us both, but this is mine sorry."

If it’s left anywhere in the open at anytime, you can repossess it legally as well. This happens with auto repossessions all the time. You don’t owe anyone an explanation as it’s yours - just take it if you can do so safely.

Not everywhere. In Sweden that would be a crime (a little bit depending on what you mean left in the open).

What kind of anarcho-tyranny is that?

European countries sometimes have a rather repulsive legal system that provides far too much protection to perpetrators.