IMO the Hypno usage isn't too unheard of, especially considering that a lot of participants in this tournament are not too accustomed to the VGC rules. What often comes to mind is, "No Sleep Clause?!" There are several ways to fight against it, but Hypno is the only mon who can passively counter it (via Insomnia) and inflict it as well (via that 60% Hypnosis @.@) However 18 uses implies that at least 5 people were running, which I agree is a bit high.
For all we know, it could just be a group of people who put together a troll (look at him and don't say you're not scared D:) team.
Also, 2 mons that I think deserve more usage...
120. Kangaskhan - 0.28% - 1 Scrappy Fake Out is quality.
102. Latias - 0.56% - 2 - The defensive form of Latios... gets 1/60th its usage.
115. Hippowdon - 0.28% - 1 Weather inducer, solid bulk, can counter its Sand Stream counterpart... and it was used once.
White FC: 0518.9529.8583
Need VGC '12 Practice? Want some tips? Feel free to PM