I do not think the incident of the Spanish flight attendant in any way reflects on the safety of San Pedro. The odds are very good that this was done by some itinerate foreigner and could have happened any where.
The biggest danger for single foreign women is making friends in the wrong crowds. Many see white girls as some kind of meal ticket and play them pretty heavily. Its like playing the lottery, one of them must be rich so you try to play them all. Besides that use common sense and you will be just fine as Diane has said.