The problem in this thread seems to be that children are seen as one homogenous group of people between ages 0 to 17. And you can either send you 5 year old to NYC without any technology by themselves, or check your 17 year old's location 24/7. Forget about any kind of in between.

Like, of course I am "surveilling" my 3 year old, I am literally obligated to. I do this with my own eyes or leave them in the care of a capable person, although depending on the situation (relative, babysitter, daycare) it is still me who is liable when something happens.

I am happy to leave my 8 year old rumble around freely as long as they return home by a time that we agreed on. We can very well also agree on them calling if they won't make it home by the agreed time, and if they don't call or pick up their phone within an additional 30 minutes, I will check their location. This can be a known and agreed upon checking. And it is about mutual trust. I trust my kid at a certain age to be responsible and keep track of time, and be available by phone (unless otherwise agreed or if they don't have a phone to begin with), as well as be where we agreed they would be, without checking. And I hope my kid will also trust me to keep up my side of the agreement. I won't check unless it's past return time and you are not picking up your phone.

This mutual trust is important in families. You deserve privacy, even if you are a kindergartener. This privacy will expand with age. This is like hiding your locked diary or leaving an open diary on your desk. You should not feel the need to hide it because I for sure won't look at it. It is yours. Similarly, you can roam around freely even with an airtag. This thing is not for daily use.

Now, does my 17 year old need an airtag? To me they are basically an adult. Hell knows I had all the freedom in the world at that age. If they feel safer knowing I could check on them when they are on a night out, maybe we can keep a similar agreement as above. But otherwise it doesn't seem to make a lot of sense to me.