Shanghai delivery rider Xie Yu was halfway through his shift on Thursday when he realised he would end up with nearly 100 orders for the whole day, double his average number. The reason for the huge spike? Chinese consumers were lapping up offers of free drinks and discounted meals from food delivery giants Alibaba Group Holding and Meituan. “This is one of the craziest days I’ve experienced since I became a rider,” said Xie, 39, who has worked for both Alibaba’s Ele.me and Meituan over the past...