There have been times, when I was in drab, that I would see someone presenting male but they had painted nails or women's jewelry or were even wearing a skirt. I always want to say something to them and usually do, something like "I like your look. I appreciate people who aren't afraid to be unique" and leave it at that.

As far as someone presenting female but perhaps easily read, I think I would simply pass by and nod and say "Good day, miss" and let that be enough.