You guys can laugh all you want but even before the rules changed to require 50 bets (or whatever the change was) this was not a profitable offer. The simple EV calculations being shown don't exactly apply because of the restrictions on the offer.
The original rebate offer mentioned in the OP had a
maximum of 4 rebates, limited to 1 per week. So let's look at all the possibilities for betting on it, using the single zero roulette wheel as the example again. Wins are 18/37 and losses are 19/37.
First case - we take all 4 rebates. At the simplest case this means 4 bets. I'll use $1000 per bet (or per week, doesn't make any difference). The ways those can come out are:
WWWW - 5.6% of the time we win $4000.
LLLL - 6.95% of the time we lose $4000 and get a $400 rebate, net loss $3600.
WWLL - 37.45% of the time we push.
WWWL - 23.65% of the time we win $2000.
WLLL - 26.35% of the time we lose $2000 and get a $200 rebate, net loss $1800.
Average result: $27.59 loss
(5.6012%*4000)-(6.9536%*3600)+(23.65%*2000)-(26.3504%*1800)
Second case - we take 3 rebates.
WWW - 11.51% of the time we win $3000.
LLL - 13.54% of the time we lose $3000 and get a $300 rebate, net loss $2700.
WWL - 36.46% of the time we win $1000.
LLW - 38.49% of the time we lose $1000 and get a $100 rebate, net loss $900.
Average result: $1.97 loss
(11.5136%*3000)-(13.5412%*2700)+(36.4598%*1000)-(38.4854%*900)
Third case - we take 2 rebates.
23.67% of the time we win $2000.
26.37% of the time we lose $2000 and get a $200 rebate, net loss $1800.
50% of the time we push.
Average result: $1.31 loss
(23.6669%*2000)-(26.3696%*1800)
Fourth case - we take 1 rebate (this is the one in dispute really).
48.65% of the time we win $1000.
51.35% of the time we lose $1000 and get a $100 rebate, net loss $900.
Average result: $24.32 win
(48.6486%*1000)-(51.3514%*900)
The problem here is that you can't average a non-repeatable wager. EV has no practical utility to a single lifetime bet. You are going to either win $1000 or lose $900, period, the end. And the $1000 win happens less than half the time. So more often than not, if you take the single bet option, you will lose $1000. And you have nothing to average it with. And if you decide after a loss that you want to continue, then we're into one of the 3 losing options described above. So you expect to lose even more.
Obviously if every player using this offer placed but a single bet, the casino will come out behind in the long run, so it's -EV for
them in that specific (unlikely) case. But over half those players will lose $900 (51.4% of them). And 48.6% of them will win $1000. But YOU, as one player, do not have a real expectation of profit here on a single bet. You will lose money over half the time with no chance to recoup it.
So now go ahead and argue philosophy instead of gambling, and that the apparent +EV applies to a non-repeatable wager. Mathematically that's absolutely true. But then read some of the papers written on how EV isn't useful for decision making on non-repeatable wagers. This has been discussed since the days of Pascal in the 15th century. In the real world, given the restrictions placed on this rebate offer, it is not a profitable wager for any player, single-wager EV notwithstanding.
And obviously for any number of wagers greater than 1 the offer has clear negative expectation. As the number of wagers increases, the expected loss approaches 90% of the house edge (due to 10% rebate).
Last edited by NewOldGuy; 04-18-2015 at 09:52 PM.