I think if you point your camera at something and you feel something uncomfortable or have any doubt about whether or not to push the shutter....don't do it. Go by your "gut" or "conscience". I would err on the side of preserving someone's privacy. I definitely am not comfortable taking images if anyone without their knowledge and permission. Just my own gut feelings. I do not in any way want "dis" those who do this type of work, it's just not for me.