[MattKing]

Well, I realize you should not expect privacy in a public space. I mentioned that in the original post. That's interesting though that a book or exhibition or print for sale (technically commercial, as you are gaining money from it) is considered art (and rightly so) and thus considered something different. But that's the U.S. What about Canada or Western Europe?

Strictly speaking, in Canada the law will vary from province to province, because the rights involved fall under provincial jurisdiction.

Practically speaking, the situation in all the common-law provinces is substantially the same - use in a photographic art book or exhibition does not require a model release, because you are not appropriating any commercial interest from the people who are subjects of the photos.

It has nothing to do with whether or not you are selling a book - it is only related to the use you are making of the content of the image. If you are using the image to advertise something, then the subjects of the photo appear to be contributing to that purpose, and are therefore entitled to a commercial reward.

The situation may be different in Quebec. There is legislation in that province that protects rights of privacy in a way that makes it advisable to try to obtain a model release for published street photography.