I have never been pickpocketed but I also know a few who have been. The kids doing it is common. They will put mustard or something on you or something like that to divert attention. Interesting that they got into shoulder bag as Rick Steves advises using that with the straps crosswise instead of a backpack because you can't see them from behind. He also suggests carying a wallet with a dollar or two in it so that they grab that. He keeps the real stuff in a money belt. He claims that the pickpockets have taken that a few times from his front pocket. In Europe I wear a Scottevest with hidden pockets if the weather is mild enough. Not too comfortable in hot weather though. I always wear my vest on planes because it holds an iPad, chargers, and travel documents.