I too recommend the ball point for the same reason. I have heard numerous times that the characters are a little weary of sharpies because it can ruin a costume. Buy the Bic or for just a few cent more, get the pen from the resorts or park. I think they cost about $2.50 and they make a great souvie for later. Also, if they quit writing for any reason, they will replace them for free at any location in WDW.