Downvoted because this is literally addressed in the article:
> AirTag is also designed with a set of proactive features that discourage unwanted tracking, an industry first. Bluetooth signal identifiers transmitted by AirTag rotate frequently to prevent unwanted location tracking. iOS devices can also detect an AirTag that isn’t with its owner, and notify the user if an unknown AirTag is seen to be traveling with them from place to place over time. And even if users don’t have an iOS device, an AirTag separated from its owner for an extended period of time will play a sound when moved to draw attention to it. If a user detects an unknown AirTag, they can tap it with their iPhone or NFC-capable device and instructions will guide them to disable the unknown AirTag.
> AirTag is also designed with a set of proactive features that discourage unwanted tracking, an industry first. Bluetooth signal identifiers transmitted by AirTag rotate frequently to prevent unwanted location tracking. iOS devices can also detect an AirTag that isn’t with its owner, and notify the user if an unknown AirTag is seen to be traveling with them from place to place over time. And even if users don’t have an iOS device, an AirTag separated from its owner for an extended period of time will play a sound when moved to draw attention to it. If a user detects an unknown AirTag, they can tap it with their iPhone or NFC-capable device and instructions will guide them to disable the unknown AirTag.