I’m probably preaching to the choir here, but thought this facebook post about the differences between local and tourist menus had some good info.
https://www.facebook.com/share/19s56Qrxok/?mibextid=wwXIfr
I looked at the first page only and right there it's totally incorrect:
You see the "surgelato" items on almost every single restaurant, not only in tourist places.
Usually for fish or shellfish. Even in top restaurants in regions that attract relatively few foreign tourists.
By law, Indication if a product is frozen on the menu, rather than fresh (for example fish) is mandatory.
By law, prices must be the same for both locals and foreign tourists. They cannot be different.
What the law does not prohibit, but should, is the use of random posts on Facebook as a source of valid information.