Insulting teachers is not acceptable. If students who have insulted teachers are not punished it does mean that we are encouraging criminal minds of such students and indirectly creating problems for future generation. Both the life of those students who are doing such mistakes and life of those innocent students who are nowhere related to these incidents are also likely to suffer if you do not take any immediate action on such incidents. Of course, teachers who have good knowledge and also have been proven to be explaining concept in an way that is well understood by students would feel embarrassed to stay in your school or college once they are insulted.
If you take enough care to ensure that the student who has insulted is punished then teacher’s confidence level of school management would improve and thus they would feel comfortable to stay back in school. However, teachers may be afraid of saying names just because they are worried about family background of students who have insulted them or else might be worried of criminal thoughts such students might have. In such situations, it becomes your duty to consult experts from www.liedetectors.co.uk so that you could easily identify students who have done unforgiveable mistake of insulting teachers.
Once you know who exactly have done that you could warn them privately in your office room and also ask them to say sorry to teachers either in front of all or else in person if the incident is not known across all people working or studying in school. This way you could ensure that such students would not feel ashamed and thus would not get involved in some other cruel thoughts and action plans that would harm either themselves or teachers. So, make sure you follow this approach so that your students stay well disciplined.