I was in Venice with my flatmate a few years back, for three days if that--and she managed to see some famous actress in a shop. So even tourist see them but not you.:)

The funny thing was that some months later I saw Kai Owen (spell?) who plays Gwen's boyfriend Rhys on another Underground platform in Central London. So in that huge city I saw by chance TWO people from Torchwood but had to go to events to see anyone else from any other TV show or film.:)

(Also, I loved Venice--I was just about to post this without saying it, cos you know, you must be fed up with hearing it. But still. I went off on my own in quieter, less touristy areas and it was lovely.)