One summer, as a teenager, Allison Yang had a novel way of playing video games for much longer than she was allowed.

Her parents had enrolled her in English tutorial classes and a choir group. Yang would turn up but leave soon after, then phone her home landline to see if anyone would pick up. If no one did, then that meant her parents were at work. She would then hurry home and squeeze in as many extra hours on the home PC as she could.