I don't know, but I had the opportunity to go several times while working at a music store in college -- I never made it, though. I do have a cool B&W glossy of a SR4 that my old boss brought me hanging in my office.
I've been to the NAMM show twice when I was running a music store. We would hook up friends/customers with passes but they would of course have to pay for plane tickets and hotel rooms. If you have a friend that works at a music store or you've bought a ton of stuff from one ask em see if they can hook you up, its so much fun.
I've meet tons of my heroes, played things I thought I'd never get to play, and seen a ton of cool new toys.
GO GO GO if you get a chance, I sad I wish I could go, the company I now work for doesn't believe in going (DUMB).