If you have questions regarding the specific Airport it is always better to check in AIP. For Innsbruck, for example, VFR (most of the PPL pilots), Airspace D, and no restrictions mentioned in Airport info, so yes it is allowed.
And you can find Visual Approach Chart in AIP.
Categories are for commercial pilot operations, they don't apply to private pilots, so there's no inherent regulatory limitation to flying into a Category C airport. The regulations say commercial pilots must be appropriately trained, and airlines have specific rules internally for this and say who can land at them, i.e. captains only or not.
A private pilot ...
The categories you are referring to fall under a classification system internal to airlines. Related: Why is Heraklion airport a 'captains only' airport?
Any restrictions imposed by the national authority will be included in the aeronautical information publication, or AIP. Taking your Innsbruck (LOWI) example, here's what the Austrian AIP says:
Generally speaking, the short answer is "probably not" (I don't know Innsbruck).
If you look into it (as a private pilot, you should know "how" already), you will most likely find that there will be a number of obstacles in your path at the majority of large airports.
These obstacles can include (but are not limited to) :
In Doc 9137, Airport Services Manual - Part II Pavement Surface Conditions, ICAO requires 3 levels of friction to be defined at local AIP level.
3.2.11 States should specify three friction levels as follows:
a) a design level which establishes the minimum friction level for a
newly constructed or resurfaced runway surface;
b) a maintenance friction ...
Partial answer valid for Italy. (See Edit 3 for more general info)
Disclaimer: I'm not a Lawyer, and Italian legislation is a real mess, so any expert in Italian Navigation Laws is welcome to chime in and provide improvements.
I'm going to cite several article of Italian Law, which are in Italian. I won't provide an accurate English translation because ...
In general, restraining unruly passengers seems to be allowed in the EU. I could not find anything specific in EASA regulations, except the following item in the list of cabin crew duties:
In case of disruptive passenger behaviour: passenger management as appropriate including use of restraint technique as considered required.
(EASA Easy Access ...
As with the FAA, EASA places the responsibility for dealing with this issue on the crew, and does not set limits on what the crew of an aircraft can do to ensure the safety of the flight. Given the fact that EASA has an official "zero tolerance" policy towards unruly passengers, I would assume that if a passenger tries to take it too far, the crew (...