You don't have to tell them your username and problem solved.

All my IRL friends that are into crypto know that I am active on bitcointalk as I tried to "recruit" them, but I shared my username only with the few closest ones that I know for like 30 years. Unfortunately, I wasn't successful at all in my attempts to bring few crypto enthusiast here that I think would be good a good addition, and some were active long time ago but have no intention to coming back ever again, for various reasons.