I agree that smaller fields will have problems collecting this new infamous tax and that the last thing one wants is the Italian revenue chasing you for money since they will sooner or later find the owner and/or there will be a very nasty surprise for the next one visiting the country in the same a/c... 'That's bizarre, why is there now concrete slabs around the a/c now that I want to fly out of here....'
But there is a very simple solution to this: a CLEAR clarification of how this law will work in practice. I really hope Italian AOPA get the answers they've been asking for, and that's before the touring season starts. Then each one can decide and plan if one wants to go to Italy (and face the predictable charges) or use another destination.