"telling people you don't know stuff projects low status"

If it's a random stranger, I don't care about status. If it's a friend or a fellow "geek", it's probably a high status signal to send. That pretty much leaves work as the only area I'd potentially run in to this, and I've found "I don't know; but I can find out!" works wonders (part of this is that at work, I'm presumably expected to actually know these things)

I've found "I don't know, but isn't it fun to find out!" is a fairly successful tactic, but I'm also deliberately aiming to attract geeks and people who like that answer in my life :)