Anonymous wrote:If you put an AirTag in the car and he is on your Apple account, it will not alert him because it assumes it belongs to him. If he uses “find my” on his phone, he will see it. I get alerted that I left my iPad or AirPods behind at a hotel - but never if I leave them at home - so you’ll need to change the settings so he doesn’t get a pop up on his phone saying “you left your air tag behind” when he parks the car.
If you set up a new Apple ID and get an air tag, he can’t see it, but eventually if it goes where he goes for a while he will get a notification on his phone that says “unknown AirTag is following you”. It will also make noise periodically. The only way that will work is if you put it in a bag of your items in the trunk and then you can claim you were not tracking him and you just misplaced the AirTag.
What if the person has an Android? Doesn't it show up in the bluetooth setting?