Yeah I saw that. CM Punk announced a signing appearance, the night before the all in show, for pro wrestling tees in Chicago. Even if he isn't showing at the Cody show (I can't see why he wouldn't want to because he can promote himself and get his ego stroked) it's a huge favour to announce it before their show went on sale because people will buy a ticket just in case he shows up and the internet will say CM Punk and "All In" a lot all summer
The best thing is they dont have to announce anything because it's already sold out, so fans will do the hype themselves. It'll probably end up on a legitimate ppv platform too, as if Cody and the Bucks weren't going to make enough money anyway lol.