Wikipedia notes that in South Tyrol:
Polls held by the Austrian research institute Karmasin show that 54% of German or Ladin-speaking South Tyroleans would support secession from Italy, while 46% of the total population (including Italians) would encourage South Tyrol's secession.
That's a substantial part of the population, comparable to Scotland or Québec in their independence referendums.
What would it take for South Tyrol to declare independence? Is the situation closer to Spain, where Madrid declares any referendum illegal and imprisons the organisers? Or rather like the United Kingdom, where the Westminster has at least once facilitated an independence referendum, promising to respect the result?