Let's say for a moment that Locke isn't kidding, when he says that the island wants people to 'pay a price'. If I were to buy into the 'island feeds' concept (and I'm more willing to accept some variation of that than the 'fantasies come true' theory), then I'd hazard that the island wants to take their pain. So far, everyone on the island has a reason for not wanting to return home, and the island is giving them a way out...but it expects payment. Finding 'Adam and Eve' makes you wonder about the island. Any science initiative is hard to swallow, if it's been working on people this long.
Frankly, I think the beachers are dreaming, if they think that a plane is going to see a fire from 12,000 feet, if they even bother to look down...and the chance of a boat coming in their remote location? Prolly not likely...especially if no one's picked up on the SOS signal by now. Of course, I'm sure they could reach a compromise. There's no reason they have to abandon their fire to man the caves...but we'll see what happens. AFAICT, no one is truly safe, there.
Oh, and as far as the aspect of fantasy elements on the island possibly being related only to science or super-science, that doesn't appear to have come from Abrams, wherever it came from. According to Newsday, " Those eerier elements will add spice to "Lost," the producers promise, but not provide the drama's main flavor. Abrams said at the TV critics' fall-season press tour that he wanted to "make it part of the fabric of the show from the beginning" so viewers wouldn't feel blindsided if fantasy elements suddenly appeared in episode eight amid character conflict."