I would understand that the Courtyard Droll would have a "You're Welcome" card because he's a Dersite agent. But Gamzee? How did he even get a "You're Motherfucking Welcome" card? He isn't even Dersite and doesn't even form part of the Derse staffs!

He’s got one because fuck the rules. It’s a reference to the fact Hussie literally got a thing that punches his face and “You’re Welcome” on paper.