According to the PopEater Staff at TV Squad the mayor of Florence set some ground rules for the Jersey Shore cast while filming season 4 in Italy:

Renzi’s rules are pretty strict — at least by MTV standards — and they include:

• The cast will not be filmed in bars and clubs that serve alcohol.

• The cast will not be filmed drinking in public.

• The show will not be filmed to promote Florence as a drinking town.

• The show should be filmed in a manner to promote Italy (not Americans visiting Italy) and feature its culture and good food.

I assume that MTV would not have agreed to this if they had known this would be the case, since that pretty encompasses 99.4% of what the show entails.