I have never been stolen in this way, but I have to say I grew up in a European city similar to Rome when it comes to pickpockets. I'll watch my stuff (always deeply buried) and protect it like a hawk. And, due to abuse in my childhood, I can get very violent! There's pools and pools of violence in me that begs for nothing else but to be unleashed, so any excuse is a good excuse!
I'm a 5'8', fairly attractive (depending on taste) 37-year-old woman. Most people think I'm a teacher, which I'm not but indeed could be.
Anyway! Stories of fending off thieves:
When I was still a student, I was not eating properly and once passed out right after leaving a large supermarket inside an even larger mall. I was lying on the floor, vaguely conscious but couldn't get up. I was 19 or 20 at the time. A few people gathered around me. I remember a woman who kept repeating: "I know first aid" but didn't do anything. And there was this guy, well-dressed, in his thirties, you wouldn't have suspected him of anything. He said "I'm a doctor" and cut through the crowd. He pretended to check for my pulse and other stuff while reaching for my wallet, which was in my coat pocket inside my hand. I was very faint, so I couldn't really move or even speak. He tried to take it and I concentrated all my strength on holding on to my wallet while looking at him. Our eyes locked. He couldn't believe it. He stayed like this for a few seconds as I was trying to speak, then left. After that, security men from the mall came over, told me to eat properly, etc.
Another story: a few years ago I was teaching (ha!) private lessons and had just come into something like 50 euro. I went to the ATM to make a deposit of the sum. Two young Roma came up to me and did some magic on the machine and I literally saw them take my money before my eyes. I have to say they were very skilled. But, I yelled at them like I was going to kill them or call the police, and they were basically scared and handed me back the money. I chased them down the street after that (helped by two Canadian tourists I met right out the ATM), but we quickly lost track of them. The Roma were about 14.
Last story: went to my hometown fairly recently, with my girlfriend, and we went to a place known to be festered with pickpockets. They are very, very, very skilled. One of their tricks is to make you feel uncomfortable about something else (like getting too close to you while on public transportation) so that you focus on that, instead of your stuff. The one making you uncomfortable usually is there only to distract you. Somebody else is doing the thieving. Anyway, there we are, public transportation and it is FILLED with tourists. So I figure: nothing's gonna happen. At the very last minute, two locals hop in - dressed like middle-class, even affluent middle-aged men. But there was something about them that was off- for one, I felt they were just too confident. The oldest sat right next to my gf. He was just a little too close. He kept up the banter with his pal for the whole trip. My girlfriend and I never spoke. She is foreign so they would have known we were tourists. This way they weren't really sure. The thing is, these are destinations that the locals don't use. So there's no reason for them to be there unless they're pickpockets. And she noticed, even though the guy had pretty nice clothes, they were rough around the edges, etc. So nothing happened that time but I'm pretty sure the two guys were pickpockets operating as a team.