He has "backed it up" in his posts. If you read through them carefully, you can see that there is clear evidence that there are some atmospheric conditions that would allow a further northern track. Even the NHC has shifted their track ...albeit ever so slightly...to the left. The two systems that would have allowed a further southern track by merging is not going to happen. Why? Because they can't catch each other, and that was a main factor in where this storm will end up. I've posted those WV loops earlier on, you can see it clearly.
I don't think that Genesis is "guessing", either. He said, "anywhere between Tampa Bay and Sarasota is possible." Those two cities are IN THE CONE, so it's not out of the realm of possibility that it will happen.
In any case, since your area is in the "margin of error" cone, you need to start completing your plans instead of accusing someone ...who, btw, has been pretty accurate thus far...of "putting your family in danger by guessing". The thing that's putting your family in danger is called HURRICANE WILMA. Also, I will make mention of the fact that several mets, NWS forecast discussions and even the NHC itself is now mentioning how these two players + some others are beginning to pan out in the models.
I would advise you to keep yourself calm because there are plenty of nailbiting days to come. We will know more in a day or so. Right now the best thing you can do is prepare for the worst and hope for the best.