I keep mine in the spare tire. Also if he shares the AirTag with you (which you can now do in iOS 17) you won’t get that message. As for why it took so long is that it won’t always show that a tracker is with you, unless you go home (not 100% of the time, but that’s what happens to me). Also needs to be with you for ~15 minutes, then when it sees you’ve stopped and the tracker is still near, it knows to notify you (same reason why your apt neighbors AirPods won’t ping you, but your passengers AirPods would if you have a friend over).