Educators across Canada are worried about the use of cellphones – and in particular social media – in classrooms, saying it’s disrupting class and causing mental health issues. Four school boards in Ontario are suing the companies behind Facebook, Instagram, TikTok and Snapchat for billions of dollars, joining a long list of U.S. school districts doing the same.Philip Mai, senior researcher and co-director of the Social Media Lab at Toronto Metropolitan University, explains why this might be a tough case to prove in court, and how it could make an impact on how young people engage with social media.Questions? Comments? Ideas? E-mail us at thedecibel@globeandmail.com