Italy car safety

About 10 years ago I was on a business trip to Lucca (Green Bay's sister city and the "Toilet Paper Machinery Capital of Europe"). After a meeting with our client, we mentioned that we would stop and tour the old city for a few hours. Our client immediately pulled out a Lucca map and circled 2 parking lots. "Only park in these lots, they have video surveillance. If you see broken glass on the pavement, that is a hint that you should park somewhere else."
Later, while gassing up at an Autostrada service station, my computer was grabbed out of the trunk by the station attendant while I went inside to pay for the fuel. Rental car + business suit + doesn't speak Italian = "Dude, you're getting a Dell!" Happy motoring.
Also you can nailed by ZTL's in Florence and Sienna. Nonetheless, a car comes in handy when touring the small towns in Tuscany. Just don't leave anything valuable in the car, get the insurance, and park where there is some form of surveillance. Hotels often have gated parking lots, and out of the way places that are not tourist magnets should be fine.

Thanks so much....by the station attendant really! We should go to Green Bay instead! Thanks again

Rental car are indistinguishable from other cars.
I've had a car (owned, not a rental) broken into in Italy twice in nearly 3 decades living there or the 30+ times visiting there. (it was at the Cinque Terre and Florence over 30 years ago).
However I also had 6 or 7 car break-ins here in California, 5 with broken windows that I had to replace, (1 near home and the rest at BART train stations), therefore it can happen anywhere.
It is a good policy not to leave valuables or luggage inside a car. It is not a good idea to leave your Ipad or camera or purse on the dashboard (even while you are inside). If you must park your car with your luggage inside, make sure it's hidden in the trunk and preferably in a guarded parking lot, of which there are plenty in Italy. Guarded parking lots are very safe and I've never heard of a break in in any of those.
When I was living in Florence many years ago and cars didn't have all the security devices available nowadays, it was very popular to break into cars and steal auto radios (the portable type). So it was routine for us to slid out that portable radio and take it with us after parking. The one I had in my car was so old and broken up (I had purchased it from a friend who had purchased it from a Neapolitan who had stolen it in Naples) that when they broke into my car in Florence, they pulled the radio out then they decided to open the car again and throw it back inside. I think the thief probably felt sorry for me and didn't have the heart to take my worthless auto radio from a penniless student. A friend of mine didn't like the idea of having to take the bulky radio with him, so he would take the radio apart in hundreds of pieces (he was very technically savvy and could put it back together very quickly) and used to leave all the pieces on the dashboard except for some small parts that he would take with him. His theory was that the thieves would probably think the radio was broken, and in the even they still stole it, they would have a hell of a time putting the pieces back together. It worked, he never had a break in.

I've had rental cars on a few different vacations in Italy and had no problems. But I did make sure that there was nothing at all visible in the car that would tempt a break-in, whenever I parked the car. Also, as recommended by RS, I would leave the glove compartment open at night to show that there was nothing special inside. And of course, try to park it overnight in an area that seems safe -- e.g., well lit area or a parking garage.