Can I take your picture in a public space? A picture of your kids? Your kids in their bathing suits at the pool? Everyone draws the line, and at a different point. It's not boolean.
It absolutely is boolean for some people. If I'm in a public space w/o an expectation of privacy you have every right to photograph me. Same goes for my daughter, bathing-suit or street-clothes. I value the right of others to make photos in public spaces and I recognize that it applies to me as a subject.
An extreme example, but I suspect there are very few people for whom this is a Boolean issue.