Because Ender was smart and Luke was a list of words she wasn't even going to think with Ben in the room.

"Well, if my first idea doesn't pan out, maybe I'll get out the Jedi action figures I saw in town and make them act out the holos. Oooh, or better yet? The trashiest show I can find."

Karla could just see it now; Kyle Katarn accusing Luke of cheating on him and illicitly fathering Leia's baby.