I'm not very good at being able to tell if someone is trans or not. I'm not even good at being able to tell if someone is gay or not. I like the whole "live and let live" theory and generally use non-gendered words to describe someone I don't know personally. As far as transphobic people go, I haven't run into very many for a long time. But if I hear comments being made about someone who's gender identity is unclear I try to make the comentator understand that there are many differences from person to person and that having a variated gender identity is not that uncommon.