“Air tag detected near you”

Air Tag uses every Apple user's routine Find My messages to piggyback Air Tag location information for Air Tags that are out of range of the phone to which they are registered. As a precaution against using Air Tags for tracking an unwitting person, such as an ex-spouse, after three days out of range of its master's iPhone, the Air Tag will announce itself to any Apple device in range.

Only you, as the victim here, can determine if this message is benign or malicious. It could be as simple as an apartment neighbor who went on a trip without taking his Air Tagged bicycle. Or it could be your ex stalking you.

There is a different message you didn't mention which might make you feel better. That message says, "There is an Air Tag traveling with you." Same three day grace period, but much more ominous if you don't know that it is your family dog, paired with your wife's phone, going everywhere with you while she is out of town on business.

You will have to decide if you want to do any sleuthing. You can tap on the message and learn where your iPhone detected this Air Tag and its ID. Good luck.

Because someone else has one near you.