Or in the case of "you guys", the mistake is perfectly clear, but it's 1) in no way intended to be sexist and 2) deeply ingrained in the culture I grew up in.

Or in the case of "you guys", the mistake is perfectly clear, but it's 1) in no way intended to be sexist and 2) deeply ingrained in the culture I grew up in. I can understand why someone might object, but the fact is it is the standard gender-neutral second person plural pronoun around here. If my wife was going into town with her best friend, I would not hesitate to ask her "How long will you guys be gone?" nor would she give me an odd look if I did. I can easily imagine people making a fuss about this leading to a state of near constant self-monitoring, and I'd probably get excited and slip up on a regular basis...