It feels like a very unlikely scenario, but it could happen, so much so that Apple is actually looking into creating a user authentication system for future AirPods. This is according to a patent discovered by Patently Apple in which Apple could introduce some kind of authentication system to ensure that the person wearing the AirPods is indeed the owner.
According to the patent, “For example, various characteristics of the user’s ear provide an echo of the ultrasonic signal which is unique to the user. Variations in the surface of the user’s ear canal may cause the ultrasonic signal to reflect off the surface and generate an echo having a signature that is associated with the user. For example, a user having a larger ear canal may result in an echo having a longer reverberation time than a user having a smaller ear canal.”
It sounds like a very sophisticated system but could be a good way to deter thieves from stealing AirPods or from people who find AirPods left behind to claim it as their own. Whether or not this is a system Apple will actually implement into future AirPods remains to be seen.