Great question, I am going to take a slightly different view to most of this thread. Firstly I don't believe it is that difficult to pass, depending on what your definition of passing is. If passing means fooling everyone so that no matter what you do or wherever you go no one would ever realise you are a guy, well yes I agree thats almost impossible, voice is the most obvious giveaway as is the Adam's Apple. BUT if you call passing going about your business mostly being unnoticed, well that can be pretty easy. I call that blending.
Careful dressing in the right clothes to match our shape etc.. , possibly some good shape wear, great makeup and a really good wig enable many of us to cover up and present a mostly female outlook, enough to blend in and 'pass'.
Last year I went shopping at a large mall in Melbourne, in two shops I saw the slight look of surprise from the SA when i spoke, up to that point they thought i was a woman, did I pass? IMO yes I did until i spoke... clearly a lot of practice of my female voice is needed...
