Yeh, if left even for few days rust can form on & under paint chips, the overall finish is compromised and it takes longer to get rid of the rust. A mate of my dad's owns a cliff top, static-caravan / trailer holiday home with a bit of land which he rents out to a local car dealer, forget which brand but not VW, as overflow storage parking. So he regularly has a dozen or so new cars parked for several weeks on the cliff top receiving the full 'benefits' of wind, sea air & salt treatment provided by the UK's North Sea. Don't envy the future owners of those cars....