The basic idea that incentives can be used to motivate behavior is a powerful one. It works for employees, and it has a clear place in parenting, as anyone who has tried to potty-train a recalcitrant toddler with sticker rewards knows.
Education campaigns ... may not be enough, at least not alone. If people have no incentive to avoid AIDS on their own, even if they know everything about the disease, they still may not change their behavior.