I suspect the vast majority of violations are committed by people who don't give a s**t about the rules to begin with. So while holding a written test may reduce unfortunate incidents caused by ignorance, it will do nothing when it comes to those bent on doing whatever the heck they want to do, so long as they can get away with it. Enforcement should be beefed up, the penalty of breaking the rules made dearer, so that if and when a person is caught for breaking the rules, he will learn a lesson to never think of poaching again.
But then again, I'm probably living in la-la land, given how underfunded the MNR is.