A common belief is that casinos secretly ban or fear Martingale players. In practice the opposite is true: casinos are perfectly happy to let people double their bets, because the game and the table rules already protect the house. You can see why by modelling any progression in the Martingale roulette calculator.
Why Casinos Usually Allow It
Martingale changes stake sizing, not the odds. Since every bet still carries the house edge, the casino's long-run expectation is positive whether or not a player doubles. There is no financial reason to prohibit a system that does not beat the house.
House Edge
The edge comes from the zero pockets and applies to every wager. No matter how a player arranges their bets, the average return per dollar stays negative, which is the ultimate reason casinos are relaxed about betting systems. This is the same point made on the expected value page.
Table Maximums
The real safeguard is the table maximum. It caps how many times a player can double, so an unbroken recovery is impossible past a certain depth. Once the required bet exceeds the maximum, the sequence fails. The mechanics are covered on the table limits page.
Online Roulette Limits
Online tables publish minimums and maximums just like live tables. The maximum on even-money bets is always finite, which is precisely what stops infinite doubling. Different tables offer different ranges, but none offers an unlimited maximum.
Live Roulette Limits
High-limit live rooms may allow larger maximums, which lets the progression run a few more steps, but the cap still exists. A bigger maximum only shifts the failure point; it never removes it.
Why Casinos Do Not Fear Ordinary Martingale Play
Between the house edge and the table maximum, a Martingale player is no more dangerous than any other. The frequent small wins are exactly the pattern the math predicts, and the occasional large loss is where the casino's edge is realised. This is why the myth that casinos fear Martingale does not hold up.
Difference Between Strategy Use and Casino Terms
Allowing a betting system is different from allowing abuse of promotions. Casinos may restrict bonus play or advantage-play techniques through their terms, but that is unrelated to the ordinary use of a staking system on your own funds. Whatever the rules, the responsible approach is the same, as set out on the responsible gambling page.