It does increase the payoff on a wager if you’re sure they’re going to honor the rebate. Again, looking at it from a single bet standpoint, you put a million on the table, but you were never going to lose a million. You were only going to lose $800,000, so effectively, you’re betting a million to win a million, but you’re only risking $800,000 to win a million.
Admittedly, this assumes they would definitely make good on the rebate.