I had 15mins in Venice, a few years back. I went for a wee in McDonalds. There was a McDonalds on every corner.
I've not seen Confidential (I don't usually watch it, but have recorded this one because I wanted to see more of the lovely location), but the writer stated in DWM that Venice was not practical for filming because it's full of Starbucks and looks nothing like 16th century Venice.
The whole point of the story, surely, was to create an atmosphere ratehr than 100% historical accuracy. This is the reason The Unquiet Dead had Swansea playing Cardiff: because there aren't enough Victorian looking bits of Cardiff that fit the needs of the story.
Vampires of Venice did the trick for me. It made me want to see Venice properly (do more than have a widdle in Mackydees), and made me look up Tigodr online. (I know I have spelled it wrong, but I spelled it right when I googled it). Croatia looks wonderful, and it has got me wondering about a holiday there.
In short: I see no problem in a couple of people getting an Easyjet to Venice in order to make a documentary. No problem at all. It will only have cost a modest amount, and will pay dividends when the docco is released on DVD and sold overseas.
Meanwhile: