From what I've read online here and at the main gatecon website, the main 4 day pass covers things like the banquet, the cruise, etc, which are all rightfully sold out at this point anyway.
I've never had the opportunity to attend Gatecon before, but most conventions offer prices for a day pass that are slightly higher than 1/4 of the four day price, meaning you pay a premium for tardiness.
I don't mean to be a bother, and I know that I'm accidentally extremely late to this party, but I could only attend two days out of the four, and my primary focuses would be to attend some of the panels and the autograph sessions.
Most conventions that are not at capacity do allow this, and I am happy to give my attendance money both to the convention to help keep it running, and autograph fees to the guests who showed up to make it a success, but if I can't do that, I simply cannot justify spending $500-$600 dollars and a 5 hour drive.
