“over time” is key in the description of how this works. I went on a work trip with a colleague recently and it was only about 24 hours after we met up that my phone notified me there was an AirTag following me, because she had one on her car keys. You wouldn’t be notified straight away.
Apple and Google deliver support for unwanted tracking alerts in iOS and Android ( www.apple.com )
Apple and Google have teamed up to deliver support for unwanted Bluetooth tracking alerts in iOS and Android.