In 1999, in Interlaken, Switzerland, 21 adventure tourists on a guided canyoning trip (a sport (see above) that combines rock climbing and white-water rafting ... sans the raft) died when they were caught by an unexpected flash flood. A paper analyzing the causes of the tragedy for the Australian adventure tourism industry found, among other things, that numerous factors can influence whether we under- or over-estimate the risks of any given event or venture.
The authors quote sources that say, as I would expect, that one factor is "one's perceived control of the event." We overestimate the risks of things we feel as if we don't control. But the authors note an important exception to that: we tend to underestimate the risks of activities that we undertake as part of a group--especially when we're tempted to "abandon responsibility to another in a group":
"For example, Pitz (1992) cites research indicating that the difference in perceived risk in automobile driving and flying is due directly to one's perceived control of the event. In terms of mood, a happy individual is likely to underestimate the chances of a negative event while an unhappy person is likely to overestimate the chances of such an event (Salovey & Birnbaum, 1989). Wildavsky and Dake (1990) have shown that an enduring personality trait influences whether individuals perceive events as being of high or low risk. Additionally, individuals may perceive relatively lower risk in a group situation than if they were alone. This risky-shift phenomenon can lead individuals to abandon responsibility to another in the group, or to be influenced by bolder group members (Haddock, 1993; Noe, McDonald, & Hammitt, 1983). In summary, individuals often tend to perceive less risk in behaviour that is voluntary, under personal control or undertaken as part of a group."
All this is particularly relevant to the burgeoning adventure tourism industry because, as the authors point out, "Adventure tourists typically undertake activities voluntarily and as part of a group. ... Where participant perceptions of risk are flawed, biased, or if critical information is absent," they conclude, "the individual may not be be prepared for the risks they encounter."
More food for thought.