it's pretty simple in my opinon.
I shoot with a 50d and 24-70 2.8 so it's hardly a stealth thing
Be courteous, polite, apologetic, and comply regardless of region, country. I have shot in Japan, across Canada, Mexico, Brazil, across USA.
You are going to get a range of reactions from people, even varying reactions in the same area.
If someone intimidates me, I apologize and put the camera away and walk away. No shot is worth offending anyone or getting in a fight or a brawl.
Are you earning a living shooting street shots?
I have even deleted the picture in front of the person to show that I am not going to do anything.
If you publish a picture of someone without a release and the subject finds out, they can come after you. Find a good lawyer.
Easy to defuse a situation. I am never defensive nor aggressive. Show respect, apologize, delete the picture if requested, and walk away.