I loved the Expo you had outside of Philly. It cost next to nothing, included free parking and had a top notch set of presenters. Of course the unwritten agreement was "We subsidize your learning experience, and you express your thanks by filling up at the product tables."
I don't know what Penguin's numbers looked like. But I can't imagine them losing money on it. At least at one I attended, the crowds were almost always several deep watching the demos, and buying product as fast as the dealer could swipe cards into his i-phone.