To spare the discussion as to potential interpretations of why I was asking the question, Neil was right.
Moral side of the story is the LAST thing on my mind.
The one ticket that I would have paid, I would pay it not because I feel bad about the city of Florence taking too much of a damage from drivers, but because of the practical reasons. Simple fear - value analysis. If only 100E was at stake, I would have preferred peace of mind and paid it. Since it is more, I am willing to take a chance. What I needed to know is the extent of the risk.
Also, my trip to Italy convinced me that Italians do not really care about any of their legacy. They live like there is no tomorrow.
What killed me was Vatican museums (I know it is technically a separate state) where priceless works are placed in galleries with open windows (in the summer) and have powerful lamps directed right at them.
They are happy as long as people are willing to pay to see their ruins.
When they are gone, they will come up with something else.
If they REALLY wanted drivers out of streets of Florence, all they had to do was to set up pass-controlled swing gates.
Answering your implied question, yes, I think that the mere street signs are not sufficient, and the amount of tickets they give out only proves it.
So, yeah, the question was only about the extent of the risk of ignoring the tickets, because, Norm, you can't be serious about appealing those tickets, from Canada, in Italian, with the only claim being unreasonableness of the procedure, do you?