For what it's worth, one of the High Schools I went to had their own security faculty that was always present on campus, with cops patrolling the neighborhood AROUND the campus during school hours without being in it, as to not cause, shall we say, "disruption". Most cases, we never needed the police, but there was one incident where a threat with a weapon was involved, and since the cops were real close to the school, the response time was quick. In every other scenario, the security staff was more than competent enough to handle most situations, like having to drag some kid who's acting out of pocket out of class.
Now obviously there are a bunch of factors to consider, such as what kind of neighborhood the school is in, but I feel like in my school's case, it was a good middle ground, since students didn't have to worry about that sort of tension that might or might not come with having a cop on campus, especially considering the public opinion of police from anyone around that age range. And if the police WERE needed, they were right there in the vicinity.
