I think a beard is the equivalent of a push-up bra. It can disguise and confuse. I was crushing on a man for awhile; then he walked in one day without the beard and Poof! Crush was gone! Am I this shallow? Apparently...yes!
I do this all the time. Mostly with geek related jokes. For example: I saw a lady today that kind of freaked me out cause she was staring at me and not blinking... I giggled to myself cause she totally would have survived the weeping angels in Doctor Who.