If your betting on a coin flip but person a is the banker and person b can quit at any time, does person b have an advantage. The martingale theory of doubling a losing bet doesn't work if there is a maximum bet. Start at 5 and going to the max of 1000 a person can bet 5,10,20,40,80,160,320,640. So they can bet 8 times. The odds of losing 8 in a row are 1 in 128. If there is no maximum bet, and the person can bet 50 times, what are the odds of losing 50 coin flips in a row. I know it's something like (1/2) to the 50th power. But how does this translate into more usable numbers, such as 1 in whatever? Would you feel comfortable placing a bet in this scenario?