Honestly, the three-day or something timeout before the airtag begins screaming might need some work - you don't have to wait three days if you're just dropping them into someone's gym bag or something and stalking them home. As for removing the speakers, unfortunately there's not much that can be done about that iirc (and people this handy would probably make their own tracker regardless).

Maybe Apple could detect when the speaker circuit has been broken or even check stuff like fancy resistances or whatnot... Honestly, they might have to start requiring ID registration or something similarly invasive because of how these tags can be abused so easily.