Another model release question

[JDB]

I've searched, but I can't really find the answer I'm looking for.

I'm getting ready to submit some photos to a couple of stock agencies, and when it comes to model releases, I always read that they are required when there is an "identifiable" person in the picture. My question then, is what constitutes identifiable? When might a picture that has people in, but with no discernable faces, require a model release?

This is one of my photos in question:

http://jbphotography.smugmug.com/photos/92341129-L.jpg

(yes, I know the horizon's a bit crooked ;)... I've fixed it in my master copy of the file, but this is the only one i've got online at the moment)

Or how about this one?
http://jbphotography.smugmug.com/photos/107992572-L.jpg

Just to make this more complicated... does anything change when you take into account that the these two people are legally minors (17 and 16, respectively), considering that they can't really be identified as such just from what you can see in the photos?

I'm not quite sure if what I'm asking deals more with the legal or ethical side of things... I'm just curious to hear what other s have to say.

[deadpass]

they are not easily identifiable and they have their clothes on so there is nothing obscene about them being minors, I'd say you're good.