My 2c as a civillian are: if I was so out of my head to cut myself and say that stuff, in such a tone of bravado... well, I wouldn't be in a right state of mind. I wouldn't want people running to the authorities; it would help nobody. I would want to receive prompt help for my injuries, and psychological issues. On the other hand, if potentially dangerous people get better care, you could be doing me a favour by reporting me. As for people I suspect of murder, child abuse, or voting for politicians, whether I'd report would depend on my level of certainty, weighed against risk (to public, to my job, to an innocent man's freedom). About every choice we ever make is a value judgement, but I do not envy the ambulancemen their choices.