My husband and I will be leaving next week on our trip to London, Rome, Venice, and Florence. We are each taking only a backpack and personal item (a purse for me, a messenger bag for him), and our backpacks are just standard school-size backpacks rather than hiking packs. In addition to our flights, we will be taking the train around Italy, and public transportation/metro to and from our hostels with the backpacks. We do not plan to carry them while sightseeing at all.
The thing I'm a bit nervous about is not being able to keep an eye on my luggage, as it's on my back instead of being carried/pulled (if I were to have a suitcase). I've heard tales of pickpockets taking items from backpacks without their wearers even feeling a thing. Does anyone have success (or horror) stories in regards to backpacks? Is it worth the effort to lock my zipper pulls together while we're in transit, or am I just being paranoid?