Unfortunately many learners believe it will help them obtain better marks - I can't imagine why they think that because we have experience in school of dagga smokers who regularly under-achieve.
If a child becomes very daring and confrontational we test him/her for drugs (it is part of our school policy and parents agree to testing) and 99% of the time they test positive for drugs of which cannabis is the most widely used. We've had children falling asleep in class because they were "too relaxed" after smoking dagga; we've had kids laughing and shouting and playing outside while they should have been in a class focusing on their education - they ingested 'space-cakes' during break and were too spaced-out to control their emotions and their behaviour.
If they do proper research, they will realize that schizophrenia is linked to kids who use mind-altering substances before they have fully developed; this includes cannabis.
Our school has the right to make its own rules and we do not allow cigarettes, dagga and alcohol on our campus. Dagga muffins also leads to outrageous behaviour, sometimes even more so than dagga which was smoked and it should have no room in an environment focused on learning.
The people who are pushing this legislation possibly have something to gain but the children will not benefit by it. Our experience with schoolchildren using dagga has always been negative. They do not concentrate on their work and become disruptive and make learning impossible for others who also attend their classes.