This is my single largest worry.
Living in the Northeast, we get outrageous amounts of salt dumped on our roads to go with the snow and ice. I don't want to watch the battery pack under the floor of the Model S corroded by salt water and destroyed. Does anyone know for a fact what Tesla is doing to protect the battery pack from the masses of ice, snow, water, gravel, and salt which will be thrown up against the bottom of the car in typical driving? I've been assuming that there will be some sort of solid, hard protection plate, but does anyone know for sure?