He probably wasn't there. I've met him plenty of times at various events and know his MO pretty well. He pops in for a few minutes before folks start speaking, makes the rounds, and makes a discrete exit. If he's a speaker or is introducing a speaker, he leaves immediately after he's done and provides no opportunity for Q&A, whether formal or informal. The guy's got no class. Mayors White and Lanier make themselves approachable by others. Peter Brown approaches you, and then only on his terms.