Though on the one hand you're right - that all the various thoughts of having the long, honorable tradition of providing assistance to anyone who needs it withdrawn under certain circumstances is a slippery slope - you also have to see the other side of it.
As Abby S's case clearly showed, there is a line somewhere at which point the honor in that tradition can be taken advantage of.
I'm not sure that anything was clearly shown by Abby Sunderland, other than the Southern Ocean in June is a bad idea. She was dismasted, which I think is a legitimate cause to call for a rescue. Anything else in the story about poor boat choice, poor timing, possibly exploiting the voyage to make a reality TV show, etc. is ancillary. She was in trouble, she called for help, she was rescued, and that's the way things are supposed to be.
I do see the point you're trying to make, that the tradition of no-cost rescue to mariners in distress can be abused. Activating an EPIRB when there's no real danger, calling in a false May Day, those sorts of things. And in those cases, one can and should be required to reimburse the cost of the rescue and face criminal charges. But I absolutely don't think that was the case with Abby Sunderland.