I strongly believe it should be. I go to a comprehensive school, in my last year of compulsory education and I must be honest, it is ridiculous what students can get away with. They could probably get away with murder. I was bullied in the first four years of high school. I constantly told different teachers around the school what was going on but they basically ignored me. When one of my teachers finally listened to me she told my head of year, who did absolutely nothing about it apart from give the bully a slap on the hand and left it at that. It has had such an impact on my life as well. I think I have recovered from what has happened, but imagine if there was a zero tolerance policy implemented in our educational system, it wouldn't have got so serious. Oh, and another thing, I think it would be beneficial as it would prepare us for the world of work. You don't get a 2nd chance in a work place, so why should it be like it is in our educational systems?
Schools do need to teach consequences for actions but throwing a student out of school for a mistake is a mistake in itself. The slowest part of the brain to develop is the morality and inhibitions. Students will make mistakes and get involved in undesirable activities before they even realize what is going on. It does not make them bad people and it does not necessarily even mean they will be toxic to other students. Discipline needs to be decided on a case by case basis and take all the extenuating circumstances into account.
Zero tolerance is not a good idea for an educational system, because people can misinterpret actions. An example of this is someone trying to compliment a student. That student can take it the wrong way, as an insult. Should a person be punished for doing something that was not intended? I don't think so.
While based on good intentions, I think Zero Tolerance Policy has turned out to be a 'one size does not fit all' policy that too often excludes any shred of common sense that might allow for mitigating factors. Keeping order in schools has traditionally been the job of educators, and I think that as much as possible, it is a function that should be returned to them to be carried out in a reasonable and thoughtful manner.
Zero Tolerance Policies do not allow room for any discretion on the part of the teacher, principal, or staff, regarding the behavior or meaning of the action of the student. Under a Zero Tolerance Policy, a child who draws a picture of a weapon, no matter the context, is punished to the same extent as a child who brings a weapon to school. When these offenses are clearly not of the same severity, the punishments that follow should not be identical.