Thanks for the generous reply.

In the last 15 years I have spent upon average three nights each year in Rome starting in 2002. I am not speaking of a run around, where meter is run up. In the examples I have written about all were clearly fraudulent behavior. In the case of the switched bill, I agree, a moment of inattention. My bad. But really a surcharge for a drop off outside the Vatican, being charged the date? I have spoken with other taxi drivers about these rip offs and they admit there are some crooked drivers.

I mentioned an uber like arrangement. My smart phone would pay the bill and the route would be shown along with any other extra charges. I could care less if it was uber. The taxi companies can set up such an app as they do here in Atlanta. The app you described does not interact with the taxi, just an order and a estimated fee.
slight of hand is quite common in other cities and I was positive of the bills in my pocket. You give a bill to the driver and then he shows you a different bill, usually a five.

I have always used taxis from the taxi stands. Never a rougue. I speak enough Italian to navigate a taxi ride.

I travel extensively, mostly in North America but also a month or so a year on the continent. I am an experienced traveler, but these dishonest drivers are that good.

In the end, it is only a small percentage of taxis. In the end, a few euros will not ruin my holiday. I friend once described it as “if they do not steal from you they will have to steal from each other”