I think it depends on where you live and what area of the city. There are definitely certain areas that are much more supportive.
Like LA for example. In places like Santa Monica, Venice, the Palisades, Marina del Rey, Westwood, Beverly Hills, Culver City, West Hollywood, Hollywood, Silverlake, and Echo Park, I really wouldn't be worried at all telling ANYONE. But then I think about places like where I live in mid city (not as rich of a neighborhood), inglewood, and slummy areas around downtown I would go as stealth as possible.
It just depends on where you are. Most random people that I've told in the "safe" areas I mentioned are STOKED about it. I mean I really haven't had a single negative interaction to the smallest degree. And in the unsafe areas, I am extremely careful.
I feel the same way about San Francisco, like there are even more safe areas. I mean when I went there for my trach shave I was staying with a friend in a not so hot area. After meeting some people at the local walgreens getting my meds and obviously looking trans as HECK, I wasn't at all worried about being labelled as anything but just another person.