Well since you only get 24 hours from when you first run it, you would have to power through the entire game in one sitting to return it in time. EA may be able to check if you've beaten it (end of game achievement, perhaps?) and then deny a refund. Plus they would keep track of refunds on your account. I bet if you end up returning a lot of games like that they would flag the account.
I would be surprised if they didn't think of these "loopholes".