use of photos of public places with other casual general public for commercial use

[xthene]

I intend to use photos taken on public places (such as food center) with faces of a few general public vividly captured for commercial purposes - such as to be used in a book. Is this legal? I believe this has been discussed many times. I did a google and while there were discussions on similar matters, there don't seem to have a definitive answer.

 

[catchlights]

seeking a legal advice?
You should consult a lawyer with this.

even a lawyer not specialise in this area won't give you an answer, how can you ask lay persons here for opinion?