I suspect it's the staff of the website.
I tried but before minutes of the end of the contest some odd things happen to it let you get in the top.
No online chat or live support too
This site is a scam, so many fishy things since their early days.
Their provably fair system is not truly provably fair as founded by Rhavar.
They paid users with so small amount of money to leave good comment on their ANN thread.
They paid users to vote on pool of best gambling site on a website (forget the website unfortunately)
And I think you are right that many of those anonymous players are fake users that created by wixiplay to make the site looks alive.
where wixiplay is still new, people are aware but later on they do already had some issues about fairness which havent been resolved yet.
Plus having lots of shady stuffs happening in the site which it isnt really worth or better to stay away on this place if you dont like to lose money.