I didn't see this thread until today, so sorry for the late reply. I have two answers, expanding on what Derek already said.
1) Publishers DO come into the room. I have personally escorted them around. But they don't announce themselves - they don't want to get mobbed. They come in quietly and look around, and act like any other player. I have been involved in designer/publisher deals that came directly out of FEPH in the past 6 years. But as Derek says, this is not the actual intent of the room, nor is any interaction guaranteed.
2) Why is the FEPH a better idea than sitting in a hallway somewhere? Because of the structure. Scores of players per slot get to choose from the games that they are excited by, based on descriptions of the games being offered. So Designers know that players are actually intending to play their type of game. Designers can also ask for specific demographics for each of their slots (such as an all-female table, or experienced CCG players ONLY, etc.). In this way, we are catering to the stated needs of the Designers - in contrast to having random people show up. Sure, designers can get random people at any time. But FEPH gives them a special concentrated opportunity that is second only to METATOPIA.
Vincent Salzillo, President
Double Exposure, Inc.