Barcelona is famous for pick pockets. Yes, there is a possibility in other large cities, but Barcelona has a reputation for this. Las Ramblas, the metro, and any other crowded location that you might be in provide opportunity. However, if you are smart about it, you should not really have any problems. 1)don't carry anything in your back pockets; 2)if you carry a bag of ANY type, make sure that you carry it on your front side or if it has to be on your back, make sure someone in your group lags behind so that they can watch the bag (and nothing else). 3) don't carry more stuff than you need, i.e. 3 credit cards or excess cash 4) make a plan to be aware of your surroundings and to not put yourself in a situation that looks sketchy 5)don't walk around with your head stuck in your cell phone. I took the Med cruise in 2007. There were actually places in Italy where I felt more uncomfortable than I did in Barcelona. We stayed in a hotel right on Las Ramblas and would do it again without hesitation. Don't let the worry of these problems take away from enjoying the city because I found it truly amazing (of course, there are others on the board who had a completely opposite opinion....finding it dirty, crowded, etc). Plan to be safe and you should have a great time.