It's the second time I've been told this and I am on my second fairly major replacement of a rusted out part. That is that the Germans use salt on their roads and that causes a lot of rust. In fact on dealer told me that the Germans won't buy their used campers and so they bring them into Italy to sell.
That's a good question. I think that Italy uses very little salt or salt and a mixture of gravel or just gravel. But I can't find the actual facts. Salting roads is somewhat controversial; it has an environmental impact and it causes lots of corrosion from cars to bridges and such.