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As for GenIII, they haven't made any promises about it being free for those cars. Of course Elon probably wants to do that. But they could introduce some limits based on their Model S experience... they have a few years to collect some statistics.
I think the wording Tesla sent out regarding their Fremont SC opening is material:
Our Fremont Supercharger station opened today! Stop by the Tesla factory and grab a quick charge, for free, forever. #GoElectric Supercharger | Tesla Motors