Sure they do. But currently the minority is exploiting the majority with considerable ease. All they do is send in the food and wine, and those occasional patrols for who knows what reasons, maybe only for disease control and to limit the food used by those who can't produce rukh. However, if the citizens of the 5th district turn restless, the magicians will need to dedicate a significant amount of troops to control them around the clock, plus keep repairing the damage caused to avoid the quantity of rukh collected dropping.
It's like pumping oil from a pleasant desert field far away from people and any delicate nature compared to going to a challenging sea location requiring expensive equipment and risking exceedingly costly environmental catastrophes. But like with oil, it's only a matter of time for Magnostadt before things get complicated. It would have happened eventually without Aladdin, but with him probably sooner.