All large universities have some level of crime. In fact, UC Berkeley had three armed robberies in the past few weeks: http://www.dailycal.org/2015/08/12/crime-rise-constables-say-recent-kerfuffle/
My son attends UCSB. He has not experienced any crimes. He even lives on Del Playa and no problems. I live in Santa Barbara. I have not noticed any increase in the amount of crime as of late. When there is a succession of similar crimes, it usually involves the same perpetrators who eventually get caught and are off the street. Remember, there are over 23k students attending UCSB. With any large population, there will be some crime. The chance of any one student becoming a victim of crime is extremely slim.