That's probably one of the best parallels to space tourism and the first place we should look for lessons learned.
It is worth noting that pretty much any Everest expedition guide [and their lead sherpas] have experience on Everest, and almost all of them have experience above 8000m. And contrary to what may be implied, pretty much every person that signs up for an expedition has reasonable mountaineering experience, albeit typically at lower elevations. Still, the barrier to entry is pretty low and is primarily financial.
Ironically, one benefit space tourism has over Everest is a relatively controlled environment. On Everest, weather and traffic can be hard to predict, and psychological variables are difficult to contain. In space, you know when you're going up and you know when you're coming down. Psychological variables are going to be more claustrophobia induced rather than hypoxia or hubris (and thus probably easier to identify before the mission), and are almost certainly more easier to manage real time--basically restrain and subdue.
Certainly early space tourism missions will have a low student to teacher ratio, compared to Everest where it may be 5-6 clients per staff. Certainly early space tourists are going to be well suited for the mission because none of the tourism companies want it to go sideways; hopefully as tourism becomes more commonplace those companies will still maintain a high bar for qualification.