Salt isn't just bad for the paint, it's bad for the car. Salt plus metal equals corrosion (rust)! That's why so many northern cars get so rusty, especially in the wheel wells, because of salted winter roads. Anytime you get sea spray on the car, or drive on salted roads, you should immediately clean the car, especially the underside, the wheel wells and the bottom of the doors with a strong stream of clean water. Otherwise, it might rust.