That direction of thinking will only drive you crazy. Skepticism is good but don't take it too far.
Also there is at least some proof that it was posted 5 days ago: http://imgur.com/fkyQS and http://www.reddit.com/r/apple/comments/xvnvo/a_friend_took_a...
I suppose we can question that day4.se were really the ones who planted it... but, does it matter who planted it? The conclusion is the same.