When Billy Joel played a concert at the Ross School in East Hampton on Saturday night, he did so to an audience that supposedly had paid $3,000 a piece to see him. The not-so-dirty non-secret is that hardly anyone actually paid for tickets. Certainly Mary-Kate Olsen, crunched up to the front of the stage and looking like a tiny bejeweled bonobo, didn't. Jon Bon Jovi, looking older and hairier than we had ever seen him, probably didn't. Ditto for Steve Guttenberg. Then again, does Steve Guttenberg pay for anything ever? Though the Lizzie Grubman folks firmly refused our photographer Laurel Ptak entry, she did capture the weird scene outside of the concert. It was kind of like "Close Encounters of the Third Kind" but with "Piano Man" in the background. Most of the ladies were Eastern European models and had no idea who Billy Joel was. Most of the men would have, in any other context, taken the question "What's your favorite Billy Joel song?" as an affront to their sexuality and have punched you. But things work differently here in the Hamptons. One fella in a striped shirt gamely responded, "Rocketman. That's my favorite song." Well, maybe it's ours too. After, everyone drove drunk.