Not sure what I'm missing here, as Airtags have long worked like this - that as long as you had an iPhone or an Android phone with the anti-tracking app installed, you'd be notified of being stalked.

So if your bike thief had an iPhone, they'd be able to find the tag anyway?

AFAIK the only major difference is that it's now being baked into the Android OS so people don't need to actively download the app.