[JohnnyHumongous]

I get what you're saying... at point A we have 500BB and we say, "since we are a winning player we will for all intents and purposes never lose this 500BB." So we are gold to keep playing at this limit no matter what. But if we drop 300BB we have to say that our probability of losing 500BB is now higher than it was before. The probability of losing 500BB was close to 0%, but it was something... let's say it was 1 in 1,000. And in that 1 in 1,000 case, it has to start with a 300BB downswing first.

let's say that for winning players, all 500BB bankrolls have a 1 in 1,000 chance of dwindling to zero. Of these bankrolls, some will drop 300BB righ toff the bat. At that point, the bankrolls then have a probability of like 1 in 100 of dwindling to zero. Many people at this point reevaluate and say, "I feel the odds are now too high that I will bust out completely, so I will now go to a lower limit." But you don't have to. You just have to be aware that the probability of losing your roll went up 10-fold. It's like betting black on a roulette wheel. If you find a bankroll that started at 500BB and it's now at 100BB, you can't say, "Well we figured that at 500BB this bankroll had almost a zero chance of busting." That is like walking up to a roulette wheel that has spun black 15 times in a row and putting $10K on red because the odds of it being black 16 times in a row is so small... The original gambler's fallacy.