Right. Either you directly regulate activity, or you adjust incentives. If you suggest one, detractors say you can't do that, you have to do the other thing, an

Right. Either you directly regulate activity, or you adjust incentives. If you suggest one, detractors say you can't do that, you have to do the other thing, and then work as hard as possible to block your efforts to do the very thing they suggested you do. That's because they don't want things to change at all. But that's obviously not an option, so I tend to suggest trying both and seeing what sticks.