Do you have to get your hand stamped to re-enter?

My friends Ken and Katie recently took their many children to Disney World, where they met up with other friends for several days of merriment. Ken wrote about it in his blog. He included photos. One of them is below. (You can click it for a larger version.) Look at the sign behind them, partially obscured by Ken’s head. What do you suppose they charge for admission at that place?