tecnicas para ganhar na roleta online

You do not have enough money to double down, and the best you can do is bet it all. You then go down to zero when you lose, so no combination of strategy and good luck can save you. Strict application of the martingale strategy produces a 100% success rate until it ends with the complete loss of all capital.

No, but there's no reason they would ever kick anyone out for that. Far more likely, the player would get a comp of some kind to encourage them to play longer.