There will always be people trying to get the loot of $100. That can be a lot of money for some, and if they are also able to do it with multiple accounts, then it is a nice snack. The Duelbits team will probably look into this thoroughly and easily catch cheaters and intervene if necessary.
Yes, we know there are people who try it but $100 I don't think is a problem for Duelbits it's part of their interaction on social media
I saw several Duelbits banners on this forum they pay 30 mbtc to put a banner on the forum for a week. I estimate the total cost of their promotion in a week is around $5000-10000 so the $100 giveaway is nothing.