Consider the following generalizations about the relationship between safety and numbers.
Is solo hiking more dangerous than going with a group? Are two or more heads better than one? This is a very important question because the most logical answer probably goes counter to the usual thought process. Consider the following perspective from an unknown hiker:
I really don't know if I'm more of a danger to those I'm with than they are to me. I suppose that can depend on my level of luck, or theirs. And I'm not convinced there's a solid inverse correlation between skill level and potential for disaster. Lots of experienced folks get into trouble. I'd like to see some statistics (the real kind) that show whether people are more likely to get hurt while solo or in a group. And to take that one step further, show whether an injured person's chances are really better in a group. I don't know.
It is commonly assumed that hiking with a group is safer than hiking alone, but that is not the whole story.
Hypothetical Wilderness Hiking Situations (Group vs. Sol0)
Consider the following hypotheticals. For example, a group attempting an off-trail traverse involving steep cliffs and rock fall while not equipped with hard hats. (A solo hiker is much less likely to get hit by falling rocks?)
What about party leadership? Sometimes party members rely too much on each other and end up with a situation where everyone is responsible, but no one is responsible. (A solo hiker is much more likely to take full responsibility for all decisions?)
What about the amount of testosterone is flowing? Sometimes testosterone-fueled judgments are exacerbated in proportion to group size, which can lead to bad decisions. (A solo hiker is much less likely to make testosterone-fueled judgments?)
A final hypothetical relates to individual skill and experience levels and how much the individual relishes the challenges of solo hiking. In the words of Vick Hines [Backpackinglight.com forum post]:
I like feeling self-sufficient and self-contained. You have to think of everything, and that awareness becomes a background for the experience and heightens it.
Are the above hypotheticals the whole story? No, but they are cause to question common wisdom. Is solo hiking more dangerous than going with a group? Not always. Are two or more heads better than one? Not always.
Generalizing again. You will be safest if you hike with a group of competent people with whom you are comfortable. Going with one or more incompetent persons can put you at a greater risk than going it alone. Is solo hiking inherently dangerous? No, everything depends upon the specific situations (like those hypotheticals mentioned above).