Every time a character makes a reference to the real world (history, pop culture, places, etc), they get called out and/or made fun of by other players or npcs for being knowledgeable about what (to them) is a fictional world.

Example: “So basically Vegas?”

“HAHA, Nerd! I can’t believe you actually read the RealLife series.”

Or

“Does he look like Abe Lincoln?”

“Wait, wait, wait, you watch OutOfGame?”