Hmm, I disagree that neutral comments are a form of positive reinforcement. They are intended to direct a child to the task at hand, guiding them to take pleasure in their work instead of just seeking praise for it. At first I found it really awkward not to say "good job," but it has grown on me. I'm able to just comment on the children's work as I see it, instead of trying to phrase compliments to make them happy. The kids don't expect praise, so it just works.
And yes, we try to handle every infraction that way. But you have to understand that there are just so few infractions, and after awhile, the kids really catch on and handle it on their own. It's nothing like classrooms when I was a kid, where students were expected to handle problems in their own inexperienced ways, and adult intervention only happened after it escalated to something serious. The kids are taught conflict resolution skills early, and staff are vigilant about spotting and addressing even the slightest problems, so kids have a lot of practice with these techniques and are comfortable with problem-solving. I know when I was a kid it was kind of a shameful thing to be caught in an altercation, and we kind of tried to hide it or lie about our role, because we'd get scolded. But these kids actually don't do that; they aren't ashamed of conflict because it is not villified, and the emphasis is on how to handle it. And they really take pride in handling it themselves. They have an arsenal of techniques, and it's adorable to watch such young kids behaving so maturely. I really think that conflict resolution should be more emphasized in schools. Having young kids navigate their own conflicts is just stressful to them and makes a distracting environment. The major infractions are so few that a teacher is able to discretely send them to the principal, who handles it privately. Part of the school's philosophy is to never rebuke a kid in front of their peers.