Safe is relative. I was very saddened to read about the 28 yr. old Unibe Student. What happened here was violation of trust. The student knew one of attackers, who obviously gained her trust at some point. In retrospect, (but will all respect to the deceased), there are some basic rules that cannot be broken. You do not allow cursory friends into your private space that have the ability to overpower and harm you. If the person still insists upon entering your apartment or casa, then they really aren't much of a friend. They are on a mission, which generally is not in your best interest.
My mother, who lives in the WV countryside, recently had two 20 yr. old girls bang persistently on her door at 4 am. They said they had been camping on the river and needed to use the phone. However, the nearest river was 11 miles away and there were 200 other houses that the girls had passed on the road, before deciding to bang on my mother's house, who lives alone. After she pointed a .22 pistol in their face, the girls got the message and backed away from the front door. Common sense is your greatest protection. And it does not hurt to display some protection.
In the case of the two girls, they walked 300 ft. to the main road and got in a waiting car. So much, for the phony river story. They were looking to rob someone.
When I ride with my english speaking Dominican taxi driver, he keeps a loaded .38 under the seat. It gives me a little more sense of protection. Sadly, you cannot let you gaurd down even for 1 second, whether in the D.R. or the U.S. :tired: