Personally, I think it's perfectly safe 99% of the time. It's that 1% that's always the stinker. Even so, I like the odds.
Hmmm, 99% seems like extremely favorable odds, a virtual guarantee of 'safety', seems to me... Hell, why bother with weather routers, or even paying attention to the weather at all, with the percentages that much in your favor, and the probality that there will only be ONE
day between Labor Day and Thanksgiving that might be unsafe to depart Newport for Bermuda? I doubt any reputable router would claim a to be spot on 99% of the time, after all...
I certainly get what you're saying, and know that's not exactly what you're suggestiing... It just seems that figure might be a bit high, when applied to an offshore passage like that from the East coast to the Caribbean, in November...
On the other hand, perhaps 95% is a bit more accurate? That's the rough percentage of the Salty Dawg fleet - despite the absence of ISAF-based inspections - that DID
actually manage to complete their voyage successfully, after all... :-)