[jay_shark]

A heads up player will typically experience about 50 to 60 ptbb/100 hands or about 100-120 big blinds /100 hands .

The probability that a player with a win rate of 8ptbb/100 hands will experience a 20 buy-in downswing with s.d = 120 big blinds is :

B=-s.d^2/(2*win-rate)*lnr
Solve for r and we get the risk of ruin for this player .

e^(-B*2*win-rate/s.d^2)= r

B = 2000 big blinds
win-rate = 16 big blinds
s.d = 120 big blinds
r=1.1 %

So with that being said , there is only a 1.1% risk of ever busting from this game if we were to play indefinitely .
Contrary to some of the arguments already expressed in this thread .