Loot from a hacker after @PinkStr3ak banned him. Just really wanted to show off that i have had diamond armour before, even though i didn't get it myself XD On topic, an admin probably just dropped it. When 2.0 came out before pvp was even enabled and everyone was gathering points for diamond armour, a player had a sandstone block, and claimed that an admin gave it to him Doesn't affect anyone, so don't worry about it.
Admins usually never go on Assassination, and the odds of them dropping something like that on accident with that specific amount is pretty high.
Hmm.. well then how did they get it? But does it really matter? The wheat doesn't exactly have sharpness V on it, and i don't think i've seen any crafting tables on assassins before.