Let's be honest about this: the realistic use case for surreptitiously slipping AirTags into an SO's purse/backpack is when someone thinks their SO is cheating and wants to catch them in the act. (To be clear, I don't endorse this. I'm simply pointing out that it's the realistic use case.)What WaPo highlighted is that a stalker abuser could stuff an air tag in the bottom of their SO’s purse/bag - where any audible chime would be muffled - and if their SO uses android, he/she/they would be likely none the wiser, yet the stalker would have very accurate location data on them.
The reason that's the use case is that the AirTag, like any surreptitious tracker, is "one-and-done." If you're trying to use it to control the person's movements and prevent them from visiting certain places or people, then by definition you are going to have to reveal that you're tracking them. And if they consent to being tracked after that, then there's no reason you need to waste money on an AirTag or Tile; you would just turn on tracking on their phone.