There are cameras in many large Italian cities - not so sure they are hidden. "Restricted" traffic zones, called ZTL's in Italy, are clearly marked... although sometimes visitors do not realize until it's too late. Anytime you drive in a large city you need to be careful. Rome and Florence are by far the most restrictive.

You might look at this post about the restricted zones in Rome: ZTL zones in Rome

On the autostrade there are also cameras set up with radar to monitor speed. Many folks unknowingly drive through those. Best advice: Stay below the speed limit!

In town, there are also cameras monitoring bus/taxi lanes so you have to be careful not to get in one of these. In this posting, the first video shows a clearly marked bus lane... but the video on Largo Argentina shows a small "do not enter this way" sign that most people don't realize they've driven past until the police pull you over...

Often it's best to just avoid driving in larger towns as the signage can be confusing to many visitors.