You also have to remember that not everyone is opposed to being photographed, in fact a lot of people love it and are natural "actors". I've seen lots of great street photographs by the greats, and said to myself, what would I do to get that shot? Lots of it could easily be coming upon an interesting scene/event and then asking someone to "do it again" or to play with people and get reactions.
I think you are absolutely right, doing street photography in the shadows may probably be less effective than being an extrovert and playing and cajoling with people. And in doing so you are also far less threatening to them.