Correct - even on dry days, there is usually a powder on the roads that will form on the finish of the car.
Also, keep in mind that those summer tires aren't going to stick very well in frigid temperatures. Not that you're automatically going to have an accident or anything, but the tires won't stick well at all - not as well as they do when it's warm out, and not as well as a winter tire sticks in frigid temperatures (even on dry roads).
Besides, I enjoy having my liability and collision coverages turned off all winter long. Saves a bundle of cash.
Mine hasn't been out yet. I'm waiting for the first track event I do in the NSX. Probably later this month.