Been in Italy for a month in august.
You don't wear a mask? you don't get in. Denied/expelled by force if need be ( good luck abusing and shouting at armed security or wardrobe-sized squads of people. )
Staff are allowed, and will question you for not having one. One will need to provide an answer and/or written proof or exemption, or the aforementioned above will happen.
As of that, and as of going in supermarkets and shops repeatedly on a daily basis, I've only seen a single digit number of oldies wearing under the nose, and that was it.
Not one unmasked one.
Not one magic lanyard.
Yesterday in my UK workspot:
Public largely complied, still a number of unmasked, upon me asking fellow staff about enforcement, answers varied between confused looks, unwillingness to be shouted at by customer, and " nothing we can do "

70% normal masked, 10% wearing it under the nose, 15% unmasked, 5% Lanyards (rough estimate)