Beverly Bunn is the first person to speak publicly about the recent tragic deaths of three participants in a sweat ceremony gone horribly wrong in Sedona Arizona.
I have personally participated in two sweat ceremonies, and I never witnessed anything remotely like what Bunn describes (scroll down for links to news stories about her interview). Both of the ceremonies that I participated in were extremely rewarding experiences. They were also both done by very different groups using very different approaches. But one thing was made absolutely clear to all participants: anyone was free to leave the sweat lodge at any time. In fact participants were encouraged to leave if they felt the urge to do so, and we were explicitly encouraged not to stay just out of pride or a desire to "tough it out". Another thing that was the case for both of the sweat lodges was that the groups were small - less than 15 people. And in at least one of those sweat lodges there was at least one person who did leave, and this was absolutely no problem.
The bottom line is this: if you are participating for the first time in a sweat ceremony with a group that you are not intimately familiar with, make sure you are clear about the logistics and the ground rules. Use your own judgement, but as far as I am concerned (and my experience is very limited) I would never participate in a ceremony in which the leaders did not make it clear that leaving at any time is OK, and that this is logistically possible. The size of the ceremony is also very important because those who are leading the ceremony need to be able to keep track of each person to guarantee that everyone is OK at all times.
According to the only eyewitness account that we now have of the sweat ceremony lead by James Arthur Ray in which three people died, these basic, common-sense guidelines were not only ignored, the opposite was done. I have no idea of the veracity of this one person's testimony, but I also have no reason to question that person's sincerity or memory. According to that one account there were clear signs that many of the participants were in serious trouble, including at least one person who was vomitting and two people who were unconscious and unresponsive. Multiple online sources have the original AP story: look here and also here.
At this point I could care less about trashing James Arthur Ray or taking cheap shots under the heading of "cultural appropriation". The important thing is for people to be educated about what can be a very valuable spiritual tool. Any kind of serious spiritual practice (especially when you start throwing around the word "warrior") is for people who are ready and able to think for themselves and take responsibility for their decisions. There are no guarantees. People fall over dead walking down the street. And the quest for enlightenment is not really suited for the risk averse. But even warriors try their best not to get themselves killed needlessly.