I suspect that most of us do not hear of hardly any incidents where someone who is armed prevents a crime. I am a retired LEO ( Deputy Sheriff, Chief of Police and Senior Detective, 41 years on duty) and I know of a large number of cases where armed persons could have, or in fact have prevented a crime.
Personally, I have investigated both types of situations where a person with a firearm could have, or did in fact, prevent further harm.
For example, a few years ago, near Cotopaxi, Colorado, a sleeping camper was killed and carried out of his RV trailer by a bear. In Rocky Mountain National Park, a short time back, a woman was killed and two of her family were injured by a bear while camping over night. Just above Idaho Springs, a jogger was killed by a Mountain Lion, as was also a child in Larimer County Colorado. I investigated a breakin to a PU Camper by a bear near Marble, Colorado while two tourist ladies were in the camper. I could list quite a few others.
The reason most in the public do not hear of these situations is because the news media rarely reports the prevention of crimes. They only report the successful activity of crimes and criminals after the crime.
Here in Colorado, I personally know of three RV crime victims, while parked in campgrounds, plus another RV burglary while the owners were not present, just in the past year.
I also have investigated numerous instances where an armed person was able to prevent a serious crime, more often than not without firing a shot. During my years on active duty in one of the rural areas of Colorado, I was called to investigate more than one criminal action involving victim campers in the National Forest Campground every year, involving people, not involving animals, including homicides, roberies, etc.
As a retired LEO I would not even think of going unarmed. Check the Crime reports published each month by the NRA publications, and/or the Uniform Crime Reports, published annually by the U.S. Justice Department and you will note that annually there are over 100,000 crimes prevented anually by armed citizens.