I used to get called "sir" all the time when I had spiked hair. (um, yeah... hourglass figure, pink shirt, big dangly earrings = "sir")

Even with my longer hair, I'd probably get called "sir" if I wore a Dopers Suck t-shirt. There's something about being tall and having a big boney face and being interested in bikes that just leads to the assumption that one is male.

Except at my LBS, where they have so many gay and TG and GQ (GenderQueer, not Gentleman's Quarterly) customers that no-one makes any assumptions about anyone. You love bikes, you're cool.

(I got called "sir" at REI bike dept last year. And I had a pink bandana on my hair girl-style! I was so traumatized that I went upstairs to the women's clothing dept and ranted on the first female salesclerk I found. She apologized on behalf of REI. She was much cooler than I was...)