[wikfwikf]

If you did this you would have to make the amount of money required very high (hundreds of Euro) before it would tip the balance on the number of people there at peak season. Then you would exclude budget-conscious travellers without raising any revenue for city services which tourists consume.

I travelled to Venice as a student. My girlfriend was from Australia, that was the one chance in her life to go to Venice. We lived on low 10s of Euro a day and would have been eating sandwiches we made in Venice and pasta we cooked for dinner. We could have paid 10-20 Euro as an entry fee (as we did for the Uffizi, the Vatican museum, etc.) but not 100 Euro, even for 'Venice Money'.

The other thing this measure would encourage is higher prices and scams. People waiting near the train station offering to change Venice money for real money. Shops selling cigarettes and other high-value stuff at a markup for Venice money. Low-quality art and souvenirs being targeted at tourists who haven't spent all their money on the way out (as used to happen in Warsaw Pact countries which had currency controls). Higher prices on basic food and drink as cafes know that tourists will have a 'sunk cost' feeling.

[TimPC]

Some of the problems are solved by modest ticketing. As mentioned if you have 5 million visitors a year and 50 euro tickets you make 250 million in revenue. For the city proper being down to 50,000 people that’s $5,000 less in property tax per year if each person has one property. Given multiple people per property you could probably lower property taxes to zero and offset the higher cost that comes from tourist prices with reduced taxation.