It's explained in the linked BBC[1] article: "The machines dispense strips of toilet paper measuring 60 to 70cm (24 to 27.5 inches) to each person. They will not dispense more paper to the same person until after nine minutes have passed. Visitors to the Temple of Heaven park's toilets were taking excessive amounts of toilet paper, some of whom were seen stuffing their bags." The photo in the article shows that the automated paper dispensers are located outside the stalls. Without even talking about an Orwellian surveillance society, this seems like an over-engineered, inconvenient, and expensive solution to a minor problem.