I wonder, if Tesla were to harden the protective shield of the battery pack and issue a recall for the existing vehicles, they could just deploy the new battery

I wonder, if Tesla were to harden the protective shield of the battery pack and issue a recall for the existing vehicles, they could just deploy the new battery packs through the automatic battery swapping facilities in the supercharging stations. The costs would probably be much lower than normal car recalls, and it would also be an interesting value proposition for the owners: "zero downtime, you get for free a safer car and a fresh battery". Anyway, the more I hear about Model S the more it looks like an exceptional engineering feat.