So I had the opportunity to re-assert my nonbinary status in chorus rehearsal* the other night. We were rehearsing a number where we were separated into groups and singing a round while coming out onto the stage. Due to absences and other things the singers originally assigned to these groups were getting shuffled around. The singer who was put in charge of musical direction by our director (who could not attend this rehearsal) suggested, "Let's have two girls and one guy in each group." I said, "Well I'm neither, so where do I go?"
I pointed this out in a matter-of-fact way, not trying to act all offended. But I did recognize and point out that he was trying to create a ratio based on people singing the higher parts vs the lower parts. And for this particular song I was singing the higher part, but for the following song would be singing one of the lower parts. And neither of these songs had any gender cues in the staging or lyrics (and we were all wearing identical costumes).
I might be the only nonbinary-identified person currently in our chorus, but I'm not the only one whose ever sung in a section where most of the members are of a different gender. Our cis male director is a countertenor, a voice that fits in with the generally-female alto section, so he understands this, and is always careful to say "sopranos and altos" instead of "ladies" and "tenors and basses" instead of "gentlemen".
There are many cases like this where people make completely unnecessary assumptions based on gender. S. Bear Bergman's article about raising a gender-neutral child comes to mind. He relayed a story where he went to get lice shampoo from a pharmacist and the pharmacist asked whether it was for a boy or girl. Bear asked what could that possibly matter, and the pharmacist said that girls had longer hair so would need a larger bottle. Maybe because I've lived in the SF Bay Area for over 20 years the idea of assuming that hair length has anything to do with gender is completely absurd, but many people still make assumptions like this.
I'm certainly guilty of making assumptions and casual (mis-)gendering myself. One habit I'm trying to break is referring to groups of people as "guys" independent of their gender. I know "guys" is generally understood to be neutral, but it isn't really. Otherwise, I should also be able to refer to a mixed-gender group as "girls" or "gals". But "guys" and "gals" are both gendered words. It's just that the masculine version is considered neutral as masculine is seen as the default. That shouldn't be the case.
Saying "folks" or "friends" sounds forced to me right now. And as I've often lamented, there's no gender-neutral equivalent to Sir/Ma'am/Miss, but I rarely have occasion to address anyone with those honorifics. It pays to be mindful, but it's hard to break ingrained habits. I try to remember that when people mis-gender me too. Change takes time.
* Dance-Along Nutcracker 2013, Dec 14-15. Get tix here.