playBunny: I think, therefore, that on balance you should never accept the double in that game because of the great chance of being gammoned.

In this case though, the gammon was irrelevant since the match would have been over anyway on a loss, and all that you need to consider is the win/loss %ages. These may be tainted by not playing for a gammon, so I suspect that the actual chances are slightly lower than 27% and the rejection of the double is correct, but not by much!!