Filipe Espósito, 9to5Mac:

While Apple mentioned that users will be able to locate lost AirPods with Precision Finding, iOS 15 will also link AirPods with your Apple ID to ensure that you can easily find them anywhere.

And:

To achieve this, the AirPods will finally be tied to your Apple ID. As spotted by 9to5Mac in the iOS 15 internal code, lost AirPods will continue to send their location to the owner through the Find My Network even if someone else connects them to another device.

Good to know.