It's a common and fun way to make a noob angry that you're breaking the rules before you google it in front of them. I've had tough times "proving" it before Google though!
Also had that happen in a school tournamen when I was young! Nowadays, over the board I try to force it in a first game with a new person to see if they know it and if they don't take my piece, I'll bring it up to prevent it being a problem later :)