It shouldn't matter whether it's illegal or not. The issue I have with it is neither legality or the fact that people are taking these photos without the subjects' knowledge. It is that these same people are posting the photos without the subjects' permission. Everybody has a right to privacy and we, as individuals who most likely value our own privacy, should respect that right.
Edit: Sorry for the recent OT posts. I just wanted to share my opinion on the matter. In other news, I saw a student here at RPI wearing a pair of Sennheiser Momentums on his way into the dining hall for breakfast. I've never actually seen someone use a pair before now, so it was pretty cool.
Edited by C.C.S. - 2/1/14 at 6:56am