@Aki,
I think just like all the organization, the legit traffic on corporate networks is like zero, most of the traffic just feeds the user's internet shopping, mailing, Facebook needs. And I think enforcing legit traffic is just so hard, not just for emails but also for internet traffic. Anyone who has worked in IT knows how hard it is to enforce rules, and I don't think it has anything to do with impunity in Kenya, it is a worldwide problem. People call you Gestapo! when you want to enforce simple website filtering, and complain how their rights and freedom on information is threated. And you know management always sides with the masses, and also the management types and the worst offenders in any case, partly because they mostly have nothing else to do.