just read through the article provided by SpringHeeledJack.
This does indeed explain a lot. Not that it is surprising, mind.
So practically, what the Italian government does now is to place every living being on this planet, Italian or not, under the general suspicion of being a tax evader and therefore implements measures to deal with that.
Within Italy, as the article shows, this may have merit.
However to take foreign aircraft (or car or yacht or whatever) owners de facto hostages is something that does not go at all.
So what needs to be made clear to the Italian government by the EU as well as the international organisations is that while they may investigate their own citizens and residents within their jurisdiction as they deem fit, but albeit within reckognized judical practice (innocent until proven guilty), they have no place altogether to impose these rules on aircraft on normal ICAO international flights, even if they do have a prolonged stay on Italian soil.
The question of whom to tax and whom not will revolve rather about the ownership of the said item and the residence of the owner. As I understand it, a residence permit is required in EU practice if anyone stays in a country other than his own for more than 3 months? So if they went that way, 3 months, plus exemptions for tech cases e.t.c, they'd have a case of sorts.
48 hours however is totally ridiculous and arbitrary. Plus, I do wonder what will actually happen once the first biz jet with VIP's on board gets actively blocked from departure unless a randsom of several hunderd thousand are paid? latest then, I reckon that some powers that are will wake up and take action, such as blocking Italian assets until their citizens with their property are freed without pre-condition.
Best regards
AN2 Driver