Sometime in May there was a talk at MIT that asked if XO laptops could counter violence in schools. I have no clue who gave the talk or their opinion - the tweet only links to a map of campus, not an explanation. Regardless, I can tell you the answer.
XO laptops do NOT counter violence in schools
Any technology by itself, be it laptops, mobile phones, FM radio, or handguns will not stop bullying, abuse, or outright assault. Only concerted change in the behaviors of people will reduce violent acts. That change comes through personal re-evaluations of the benefits of physical intimidation and reinforcement by the community that abuse will not be tolerated.
Beyond that, it doesn't matter if they have XO's or Xboxes, the technology is benign itself and will be used by the oppressor or the oppressed in every way imaginable. So please, do not instill in an inanimate object the powers that only animate beings can express.