Our daughter had her wallet and passport taken on Las Ramblas (unzipped the bag without her noticing) and made it to the airport before she realized it was missing.
She went back to the Consulate and had a new passport a few hours later. And she wasn't alone that very day.
Later that year, we were in Barcelona with a guide and I noticed her giving a man
a very decided glare. She told me that he was a pickpocket known to the guides and that they knew most of them in the area. That should also mean that the police could, theoretically, know who they are but alas....