If a tourist is in a Milan hotel would they be allowed to leave Milan to fly out of MXP?
Or if a tourist were in an area outside the lockdown region, e.g. the Aosta Valley region, would they be allowed to transit through Lombardy/Milan to depart from MXP?
Edgar, your guess is as good as mine. This appears to be a "quarantine light": Pretty please stay at home, but we aren't actually doing anything to enforce a quarantine.
This map shows the "lockdown" area (grey): https://www.srf.ch/static/cms/images/960w/39ff97.jpg
It is actually three separate areas. It would take the whole Italian army to block all routes in and out of that.
According to Swiss TV, the Italian/Swiss border is remaining open for commuters: https://www.srf.ch/news/schweiz/coronavirus-aktuelle-lage-grenze-zu-italien-bleibt-fuer-grenzgaenger-offen
"Italy's foreign minister Luigi Di Maio has confirmed that the border between Italy and Switzerland remains open for all commuters. . . . . All employed persons can continue to move about in order to get to their jobs, equally between the Italian regions and Switzerland and Italy."
Strange kind of quarantine.