With regards to the merit requirements... You should have just made a rule that only accounts created PRIOR to the timedate of the thread creation are eligible to enter (prevents people from spooling up new accounts to try and flood the giveaway).

Sure, someone could already have a massive amounts of alts that they're going to use to just throw in multiple guesses... but considering this was supposed to be an educational giveaway... and it was posted in B&H... limiting via merit would probably preclude a lot of "beginners".