We just returned from Rome, Florence and Venice and did not have any problems anywhere - no attempted theft or any problems.

However I don't entirely agree that you can simply "take easy steps to make it impossible". Certainly you can take reasonable steps to prevent it and to minimize your potential losses. But if you are visiting the Sistine Chapel, Trevi Fountain, or taking a train from Florence, or walking though St. Mark's Square during the afternoon, you cannot avoid the crowds or even people brushing up near you. Of course you can be aware of your surroundings, keep your eyes on people, keep your hands free, put your wallet in front pocket, etc. But you cannot stop a criminal from making the attempt. If your hands are free you can slap him away, yell, etc. On a recent trip somebody sliced Mrs. B's purse strap at the OAK airport (inside security). She caught the purse but did not see the culprit. You cannot prevent that but you can be aware of surroundings and protect your possessions. Yes you can try to avoid crowds and tell approaching vendors to kiss off but casual contact (e.g. on subways) is unavoidable.

The best advice is to ensure that any losses are minimized. Keep your passports, extra credit cards, ATM cards and cash in the hotel safe. Only go out with 1-2 credit cards and a reasonable amount of cash.