Korea absolutely has much stricter defamation laws to the point I'm afraid to give a restaurant less than 5 stars on UberEats. I kid, but you really gotta be careful what you say about people online or even in person. I had a co-worker call our boss a liar and get sued for it. Dude was definitely a liar.
They've been "confiscated" at the beginning of every school day and put into this case with a bunch of pouches for phones since cell phones became a thing in South Korea, but apparently this was a decision left up to the school principal. The last middle school I worked at didn't allow students to bring phones to school at all. I've never heard of any schools that allow phones in class outside of some supervised activities where they might need it. I guess this law just makes the rule mandatory for all schools.