I picked up a copy of the poster that launched this thread from El Jefe Himself at SPX, and I believe he told me they wouldn't be available at the show because there was no way he could make any money off of them there. I'm not sure if it was the D's or the club that he would have had to give the posters to, but whoever it was would have kept all the $$. Since he only does a limited run of each poster (in this case 80), and a certain percentage go to the band and the venue, he wants to maximize his profits on the rest of them.
When I went to the Sunday show, I assumed I wouldn't be able to get it signed anyway so I left the poster at home. It turned out that the merch guy had some copies of it himself, and after spending a little money and giving him a fat tip, I asked if he'd be able to hook me up with signatures the following night. Instead, he offered to get one of his copies signed during the day on Monday, which I then traded for my own at that night's concert. Now I'm the proud owner of print #30 of 80, with all six band members' signatures. Most of them signed on the elephant, but given how much new/touring band member Lisa resembles the girl in the poster, I think it's amusing that she signed on the girl's arm.