The kids concerned were indoctrinated at islamic classes, and are "hafez-e-Quran: ie, they can recite the entire Quran from memory.
The malaysian state schools are extremely anal about their uniform dress codes... songkoks can pass, but I suspect these are PAS inspired agitators trying to make a point about UMNO (the ruling party, and their secular courts and judicial system inherited from the Brits) not being "islamic enough."
There is constant tension between the two opposing parties, and the area is in the zone where reversion to "true islam" is playing out. Its close to the states of Kelentan and Trengannu, where all out sharia was imposed on the population by PAS, to the dismay of bumiputras (muslim malay) and non-Muslim Chinese and Indians alike.
What will it be next? A reversion to fullscale cannibalism ~ such as was practiced by their ancestors until Admiral He came in with a gazillion Chinese to teach them some manners?