I actually wouldn't say that. If I knew the gender of the person I would say it. If I didn't I would absolutely say "he/she". We may... but I honestly try not to. I'm not super sure about my grammar, but I still try to speak clearly and mixed pronouns bug me. But who knows? Our language is evolving - and that may be the next evolution. And why not - we've got to be able to figure out a way to have these discussions. As lines of gender continue to blur in society, so will our rules of grammar that are based on gender. I wonder how other, more gender specific languages will adapt? Spanish ends words with "A" or "O" depending on the object. German is full of verb conjugations based on he or she. Exciting times!"Why not talk to your HR rep and see what they say about it."
We all subconsciously use singular they every day of our life, all the time.