Hong Kong’s ATM network has been hit with a surge in withdrawals by customers using China UnionPay bank cards in the wake of facial recognition technology being introduced at cash dispensing machines in Macau. Monetary chiefs in Hong Kong have declined to deny or confirm information obtained by the South China Morning Post that ATMs have seen a “staggering’’ rise in withdrawals since the casino hub introduced the recognition technology in May as part of a bid to stem illegal capital flight from mainland China.