Originally posted on 11/15/2013:
Grey area I think...not a big enough issue, but the IRS has been nit-picking things like airline miles and CC rewards in recent years...something like this could very well technically fall into taxable income category.
That being said, they wouldn't find out about stuff like a gift card unless you reported it. Only stuff that goes through a bank account (sportsbook or fantasy cash when withdrawing) would be likely to show up.