Around here the schools usually state the instructor´s background (more often than not military survival instructor). They also post an agenda of the course (or courses if there are more levels).
That agenda allows to evaluate the course on basic level.
Based on those agendas I decided that the courses would be almost worthless for me (ETS and this forum have a big part in this). However I can imagine that the course may be dangerous for the student even when the course is good. The mindset is along the lines of "Now you are in a situation where you need a certain skill set to survive. We´ll teach that.". None of the courses I looked at had the topic of "How do I avoid needing that skill set in the first place" on their agenda. OTOH climbing a hill and making a phone call to get evacuated may defeat the purpose of a survival course.