- contact the airport shortly before the flight and verify all the stuff (Customs PNR, avgas, etc) and verify they sell avgas to visitors as many declare it "available" but actually for the aeroclub only
- if you don't get a confirmation, don't fly there
Yes: the procedure is
1) Call them to get an e-mail address to send a landing/ avgas / handling / parking etc... request.
2) Send the e-mail, but don't make it longer than 15 lines or they might be discouraged from reading it (Italians are as bad in a second language as the English).
3) If you don't get a reply within 48 hours, call again to chase the reply.
Refusing a landing would be quite extreme (unless it says in the AIP you need a landing slot, but then they would stop you at the CTR or, if on an IFR flight plan, at the startup request), did you really have that ?
Refusing avgas / handling or parking would be
quite common, especially in the summer as things get a bit busy. So don't book a hotel or a rental car on a non-cancellable basis unless you have the e-mail confo.
There seems to be a bit of an optimum between price and service at an Italian airport. Usually you can read between the lines of the AIP whether you are welcome in your type of aircraft or not. Salerno is one of those places where you would be welcome. Naples is one where you wouldn't be. But it is not always size that matters : Florence for example also has v@ff@nculo written all over it. Don't know about Malpensa, but I cannot imagine them welcoming you for anything less than 250 EUR... and you can have buzy airport kicks for 1/10th of that price in Geneva
