called the monte carlo system, as in theory no table limits there.
watch roulette and you will be amazed how long runs on 50/50 results go the same way.
it sounds unlikely, but every other time you will lose first spin, before long you are at table limits, plus you have walked into the casino if your example with over 5 grand, and the 8th spin is as likely to lose as the others, so next bet is ?5120, to recvoer the the ?5115 you have already lost so you got there with over ?10k.