One thing about a black camera is that it doesn’t look “old fashioned”. Cameras are always black or space-age future silver now days. Never chrome. Also, a black Leica makes you turn invisible. Especially if you have an f/1.0 Noctilux on it.
In my limited street shoot experience, I just give a big old Winogrand smile and walk really fast. I try to look like I know what the heck I’m doing. Usually I’m gone before I have to explain.
A few times someone has caught up with me to dress me down. I don’t think my escape route has been the same two times — I’ve claimed to be a student, I’ve sputtered uncontrollably, I’ve openly lied about whether I would use their image, I’ve told them that I was just a hobbyist. Usually my objective is to say ANYTHING so they don’t kill and eat me.