Yeah, if you run a free and open-to-all competition, giveaway, or similar with a monetary reward at the end, you will be flooded with newbie and alt accounts. And easy way round this is with by charging a small buy in, or requiring every involved account to have earned a minimum amount of merit.

There are some things like this going on, such as hilariousandco running various football betting pools. I would definitely have joined LoyceV's price prediction thread had I known about it - getting the word out is another hurdle that needs to be overcome for things such as this.