Since you are a well traveled person, you're obviously more aware and more careful than the average tourist, yet you did get caught in Lisbon. Could have happened in any big tourist spot.
My sister in law went to Rio de Janeiro last year and was warned by the travel agent NOT to walk around with necklaces, earrings, watches, expensive clothes, photo cameras, even cell phones, that will attract the bandidos, who work very swiftly and sometimes violently to rob you.
Me, I've never had that problem, probably because I did most of my travelling when I was younger and at a time when things were very different to what they are now. I did a lot of travelling. Visited about 30 countries in 3 continents