Guys, I am living in Europe for close to 50 years. I have been all over the place. I looked "poor" and "rich", like a tourist or not. Never made any experience with pick-pockets. Most of it is just common sense. There are some rules to be observed which are different from the US:

• Leave your passport at home in EU countries, different in Russia or other strange places.
  
• Go out with a credit card, cash in your pocket and a driving license in the evening. In 99.9% percent of the cases this is sufficient for everything.
  
• Don't let people approaching you, that look different from the general public (sorry, this was too politically correct: Reports say that quite of the few of pick pockets in Europe come from a certain minority in certain South-Eastern European countries and in most of the cases you can identifiy these people. Might be more difficult for you as a stranger and it is difficult to explain without geeting racist. However, unusal clothes (different from the general public in MUC, AMS or whereever and NOT American should warn you)