Outside visitors forbidden in theory from talking to those inside the dungeon, a rule everyone knows is ignored.
Explaining to Princess Donut how much the Hunters can learn, Carl says that in theory people outside the dungeon aren't supposed to talk to those inside — even the tourists — but that everyone knows that's bullshit.
He still doubts the hunters have a direct line, especially with Desperado Club access messed up for those on the ninth floor, but expects information to leak eventually regardless.
Outside spectators whose contact rules are nominally strict and practically meaningless.