[chillrob]

That is only assuming you kept playing after he doubled up. If you decided to quit after the $6 player doubled through you, you still only risked (and lost) $6. At that point each of you are now risking up to $12. You have to think of the risks individually.

There are other reasons why you might not want to play against varied stack sizes lower than yours though. In this example you give, the $6 player actually has an edge over either you or the other large stack (you effectively have the same stack size as the second biggest stack). The $6 has an advantage because he can play perfect $6 stack poker against all his opponents, while you and the medium stack have to try to play medium stack poker against one opponent and short stack poker against another, and may not be able to choose the best play for both. If you really wanted to make the game more fair so the short stack didn't have an advantage, you could make him buy up to the size of the medium stack to accomplish that. You could then even take some out of your stack to make all three stacks the same if it makes you feel better, but it wouldn't really make any difference.