[Svip]

But that's like saying, every time you are going through security in any airport, you are detained, because - you could not - if you so wanted, simply go back through security again. But you sort of opt-in for this when you fly; you know you are going to go through security and they won't let you leave unless you are cleared.

Edit: etchalon said it better.

[pseudonym]

It's not a question of "going back through security", re-entrance has nothing to do with it. Going to a concert where they don't stamp your hand when you go through the door doesn't make you "detained".

[einhverfr]

>But that's like saying, every time you are going through security in any airport, you are detained, because - you could not - if you so wanted, simply go back through security again

I am not a lawyer but I think that the line drawn at detention is whether one is effectively told, under the color of law, that one is not free to go. By this standard, I think it is pretty clear that everyone is briefly detained when going through airport security, and that all bags are briefly seized.

If this isn't a detention or a seizure, then you are free not to put your bags on the conveyor and walk back out and the most they can do is say "you can't go further in." But if there are threats of fines, etc. then it is a detention.