Schools and other authorities around the world are warning parents not to let their children watch the hyper-violent Korean drama series Squid Game. In Hong Kong, the English Schools Foundation, in a message on its mobile app, warned parents that Squid Game had become a topic of playground conversation and that the series included scenes of violence, death, sex and gambling. “We suggest parents remain aware of what their children are watching, both on streaming TV and through social media,” the message said. “This is particularly relevant as Squid Game is trending high in popularity as the content is not...