A "Martingale" is a failure betting fallacy, and a casino can only hope for players so stupid. It will result in a player going bust far quicker than the casino.
I can believe this. I played over a thousand rolls this past week alone in the 50% bracket. I always start out with .05 BTC, and I've gone on 7x losing streaks (Lose .05 -> .10 -> .20 -> .40 -> .80 -> 1.60 -> 3.20) about a half dozen times. However, after looking at my trade history, I've NEVER gone beyond 5 straight wins, ever. 50% my ass.