If it's a 1 in 10,000 chance, and if Minecraft has been out for 3 years (that's quite a generous number) you'd have had to boot up Minecraft almost 11 times a day in order to have likely seen it by now.
I'm it's overlooked more often than not. Notch probably meant to keep us off balance thinking it was a hidden feature (aka, "removed herobrine.")
The Meaning of Life, the Universe, and Everything.
Yes, a few times. Didn't even know that it was the big undiscovered secret until it was revealed. I just thought it was one of those Mojang welcome screen oddities you read everytime. The reason i noticed it those few times because it triggered the name Rincewind in my memory. Else i'd have never seen it.