Hehe, I tend to use gender-neutral pronouns when referring to people I don't know IRL. To me, "they" is very easily also a singular reference. This practice dates back centuries.
Singular they - Wikipedia #usage
It's just like saying, "that person". Y'all know who I'm talking about, and then I don't have to assume anything. Yes, I could check someone's profile to see if they have listed their gender, but that is my personal rule until I know their gender AND/OR they specifically ask me not to say they.