No one is allowed to complain about improper uses of "they" ever again. English is an evolving language, and "they" is filling the niche for "gender neutral plural/singular" pronoun at this point in time. DEAL WITH IT.

I try to refrain from using "they" as a universal pronoun when writing papers for uni, but it gets so annoying if I'm speaking of a person hypothetically and I have to type "he/she" or "(s)he" EVERY. FUCKING. TIME. Informally, I just stick "they" in. :'D