As being told here in Spain if pickpockets took less than 400€ they can go home easily but Good news as now some laws changed and pickpockets with multiple robberies now face harder law.
Them problem in BCN was that a very few number of people had thousands of robberies...now some of this gangs are moving to Paris or other cities.
Anyway, You always have to be very careful in all cities. I can say BCN is a safe city.