I agree with you that the models are not technically underage. Moreover, I know from previous articles about AA that they make the models sign releases confirming they are of age. However, I think that makes it worse and I'd like to explain why.
We already know that what constitutes porn is in fact subjective and was "officially" defined as such by the Supreme Court:
http://en.wikipedia.org/wiki/Jacobellis_v._Ohio
So what I'd like to point out is that the very reason that AA needs that little signature is because they know they are (1) making pornographic ads and (2) using models that look underage. If either of those two were untrue, the free-wheeling, open-minded people at AA would surely not resort to legal means to cover their ass.
As far as not providing evidence, what is harder evidence than actual photos of AA ads? I don't see how it's relevant what website they are posted on. Photos are photos.
But hey, I am happy to link to more. If you don't think these are prime pedophile material, I don't even know what to say... you must be one "open-minded" dude.
http://www.gamesetwatch.com/2006_07_10_9.jpg http://www.wasuvi.com/images/scan0004.jpg http://www.adrants.com/images/the_tap_panty.jpg http://www.mediabistro.com/agencyspy/original/aaad.jpg http://www.jenisfamous.com/uploaded_images/leggings-720878.j... http://www.trendhunter.com/images/phpthumbnails/21343_1_230....