Don’t do it – it’s extremely dangerous.

You can quickly get to a situation where you’re wagering vast sums of money to try to win a very small amount; ultimately you run the risk of reaching a point where you simply can’t afford to place the bet, or, more likely, you’ll reach the max stake for the table and be unable to win your money back. And yes, the casino may decide they don’t like what you’re doing and refuse to take further wagers.

Of course, probability being what it is, you’ll usually get away with this – you have a high chance of winning a small amount, and a small chance of losing a huge amount.

It isn’t a winning strategy in the long term, though – whatever you do in European Roulette you will tend towards losing an average of 1/37th of the total amount you wager, the house edge is built in. (1/74th for French Roulette, 1/19th for American Roulette with the 0 and 00).