Teachers, by definition, will be around large groups of people while working. The truth is that when many people are put together in close quarters, tensions and conflicts can arise. In such a case, the teacher is the natural peacemaker among the people involved. By giving them training to intervene in a crisis, teachers will be better equipped to handle such situations.
Yes, I think all teachers should be required to be trained in crisis intervention techniques. It seems like there are shootings in schools almost every week any more. You never know when or if there might be a crisis in any school. The best thing we can do is have our teachers trained in intervention techniques. This training might one day save many lives.
Crisis intervention techniques should be a part of professional development for teachers. It is unfortunate that this is required today, but we have seen many examples of instances where this type of training would have been beneficial. Teachers are certainly trained to go on lock down, but crisis negotiation with a student would be helpful to all involved.
Yes, crisis intervention techniques should be a part of professional development for teachers, because there are children who often go through various problems while they are students. If teachers are trained, they can see warning signs and help children cope, which can prevent more serious problems for the children later on.