Some grocery stores in KL have made it mandatory for customers to show their respective identification cards (IC) before buying subsidised rice. 

This is to prevent foreigners from buying the subsidised local white rice

Another thing to remember is that some vendors in KL are also limiting the purchase per family. In a report by the New Straits Times, 47-year-old Sharon Pooi only allows each family to purchase two bags of local white rice. Of course, this also comes after she has checked the required identification.