If they don't already know my email address and full name, then why would I add them as RealID friends in the first place? It would be nice to be able to chat cross-server/game with casual acquaintances I've met through WoW, but that's not what the system is designed for nor being marketed as.

Sure, I do wish it was more like a steam id that was just as anonymous as a wow character name, and I wish there was an invisible/offline mode. They've obviously made a design decision to make it something IRL friends are using and not game-only friends. Also makes people behave a lot better when they're no longer as anonymous as they once were .