These motivational poster series jokes typically deal with captioning any place where people would usually be, but aren't. The caption typically mentions (instead of the presence of no one) the presence of ninjas. The fact that there is obviously no one there but there are ninjas insisted on being there reflects a (over exaggerated) ninja's skill of stealth. The exaggeration suggests that ninjas are invisible.
What say you, KYMers? Entry or no Entry?