Shake Shack has been doing a brisk business on the Chinese mainland, days after the famed American burger chain opened for business in Shanghai on January 24, 2019. Queues snaked the block as enthusiastic customers waited for more than an hour to get into the restaurant to sample a menu that’s already been a hit in Hong Kong. The franchise has even been limiting customers to three burgers per visit to try and prevent touts from reselling the hamburgers and drinks to those waiting outside.