Any type of execise can be dangerous when proper instruction, progression, and limits are not used. CrossFit does have high potential for problems with these guidelines as many of the CF exercises can require very high power output and control. Especially when the moves become advanced. I can only hope that instructors are using caution and a lot of monitoring.
I like what Karin wrote about educating clients on the pros and cons of any given exercise program. A second step is educating clients on what qualifications to look for in their trainer and what types of classes to look for (i.e. is there a program for beginners or do they throw you in right away with experienced exercisers?).
Finally, I think it depends highly on the trainers at the Crossfit facility. I’ve known some very qualified Crossfit trainers who practice safe progressions for their new clients, including classes for different fitness and experience levels. I’ve also known some Crossfit instructors who I wouldn’t feel comfortable recommending.
I have seen some Crossfit videos that were disturbing but I have also talked with a Crossfit instructor who was knowledgeable and sincere.
People can hurt themselves in any style class, even including Pilates and yoga. When asked about other programs, I usually try to educate the person asking about the pros and cons of any given program and let them take it from there. I would venture to say that no client of mine would be tempted to join Crossfit. To them I could give specific recommendations because I know their abilities well enough.