Allow me the pleasure of playing Devil's advocate for a moment here.
If you're allowed to photograph me without permission are you also allowed to display the picture? or sell it? or use it to promote any personal beliefs you have that I might not share? After all its your picture.
I think privacy is an issue that is sometimes overlooked by many.
Joe, In the United States at least, what matters is whether or not you're in a place where you have a "reasonable expectation of privacy." A restroom, hospital, dressing room would be that kind of place and I'd have no right to photograph you in such a place. Otherwise, as long as I'm
in a public place, or a place such as, say, Epcot, that allows photography, I have every right to shoot a picture of you -- even if you
aren't in a public place when I shoot the picture. In the U.S., the kind of "offense" described in the example would be laughed out of court.
Once I have the picture, I can display it and/or sell it for editorial purposes or as a work of art. But I don't have the right to sell it or use it for purposes such as advertising -- which probably would include trying to promote my personal beliefs. I also don't have the right to use the picture deliberately to make you look, say, ridiculous or criminal -- in other words, to misrepresent you.
There are specific exceptions to these general rules, of course, and I'm not trying to give legal advice. Regarding any specific case you'd have to consult an attorney. But this is the kind of common sense I wish I could find around the world. Even France, it seems, is beginning to depart from the easygoing toleration of photography that made a Cartier-Bresson possible. I'd count that a tragedy.
For more information on the subject, go here: http://www.krages.com/phoright.htm
and download the .PDF file. This is a compact reference you can print and carry around with you.