Hold on, before you jump on me for asking something ridiculously idiotic...

I was specifically thinking of the tendency for people to continue gamble until they're no longer able, especially on sites where you have to pre-fund accounts (you need to deal with the bother and, with BTC, confirmation wait times of withdrawal and possibly a withdrawal fee). I don't know of any figures which'd be relevant, but I'd be surprised if a very simple coinflip site, where there's always a 49% chance of the player winning, did not actually haul a 5% averaged profit or more due to gambling fallacies (letting it ride, then believing you can recover a loss by betting more, eventually losing their entire roll with a bad series of gambles).

-So, then, why not offer a casino where the player has an edge per play (maybe even significant), but still has the cards stacked against them simply by gambling psychology? The only concern, then, is with bots, but perhaps you could just raise the stakes high enough where bot-users would be hesitant or maybe even demand some kind of flat fee to play the game. Alternately, perhaps you could have it where players need to "unlock" that "EV+" game, perhaps through a large number of losses/bets with EV- games in the casino.