I don't think the IBC can tell its members to ignore a law in black and white. I don't think the Florida Department of Public Safety can tell its members (the police) to ignore a law, either.
Rob is right in that this won't be completely and unquestionably sorted out until the Florida legislature actually revokes the law. Rob is right in that if you want to take absolutely no risk of being charged with this or having an issue with your insurance company that the only solution is to follow the written law and get the international permit.
But in view of what everyone (insurance, police, state gov't in Florida) is saying about this ... I wouldn't.