Do You Tell Someone About A Wardrobe Malfunction?

So I had to take a trip over the weekend, and this morning, in the Atlanta airport, I was behind this woman (who was having what one might call a 'wardrobe malfunction') on the escalator:

So, being the good samaritan  that I am, I took a picture of her to share with Facebook.  I figured that it would be 'okay', since the woman is unidentifiable (except to TSA and the FBI, of course).

When we got off of the escalator, and into the tram thingy, the woman that was behind me on the escalator goes to the woman pictured above and whispers in her ear, then points my way.  Of course, I was busy on my iPhone, so I was able to act like I didn't notice.  The tagged woman put the tag back into her shirt, and then sheepishly smiled my way.  I grinned a little, and she smiled and shrugged, as if to say "It happens to the best of us".

The OTHER woman had since moved to the front of the tram, and kept looking over her shoulder at me.  I think that she was watching to see if I would take her picture, too.

Anyway, that was as adventurous as my morning was going to get, I am afraid.

My question to you is this:  Would you have told her about the tag hanging out?  Part of me thinks that I should have said something, but the other part of me said "someone else will tell her".    Is it more "appropriate" for a woman to alert another woman in this situation?

Don't get me wrong, I don't feel bad about taking the picture (since she isn't identifiable), but I do feel a little something for not telling her.  What are your thoughts?