Casino self-exclusion schemes generally combine physical unavailability with reward diminution: the casino tries to keep you away, and if you do gamble, they try to prevent you from collecting winnings. Lottery self-exclusion, however, seems to involve only reward diminution. Lottery outlets will sell disassociated persons all the tickets that they want, but the state lottery authorities will not allow the self-excluded to collect large wins. In both Illinois and Iowa, for instance, "large wins" are those involving $600 or more.
If all of the monetary and hedonic reward from gambling could be removed, then making gambling physically unavailable would offer little improvement in combatting problem gambling. Alternatively, if physical unavailability were perfect, reward diminution would be superfluous. But in practice, both barriers to availability and diminished rewards are imperfect and subject to evasion -- and both make a contribution towards controlling problem gambling.
Placing a bet as a commitment to undertaking a personal reform -- a' la stickK.com -- involves a form of reward diminution: fail to reform and you have to pay a self-imposed fine. Public pronouncements of an intention to reform establish another version of reward diminution: failure to reform will cost you some respect in the eyes of your peers, along with some self-respect, perhaps. But many people trying to reform a bad habit try to institute both physical unavailability and reward diminution. For instance, they adopt a rule not to keep any ice cream in the house, and then feel guilty (and possibly lose self-respect as well as the respect of others) when they violate their rule and consume the now-available ice cream.