I recall when people in San Fransisco had an active whistle blowing campaign. Which doesn't work if thre isn't help. My personal approach is tto learn to defend yourself , even if you need to carry a sharp ended object. It helps to work out; have somedefensive training. Also travel in groups. I've seen gays beat straight guys bloody and queens hold off thugs with a twelve inch pair of scissors.
Sometimes there is no other defense, and it hepls your self confidence.