  It is important to study the behavior of a t-error correcting quantum code
when the number of errors is greater than t, because it is likely that there
are also small errors besides t large correctable errors. We give a lower bound
for the fidelity of a t-error correcting stabilizer code over a general
memoryless channel, allowing more than t errors. We also show that the fidelity
can be made arbitrary close to 1 by increasing the code length.
