Or tell them to put their phones up?

I personally wouldn’t unless there’s a test or assignment being administered and it’s because I feel like if a student wants to learn, they’ll put it away unless it’s a necessary text. Also, if you really do have to take a phone call you can step outside. Some people say it’s disrespectful to the teacher to be on your phone in class but to me that’s just taking it personally as again, if they want to learn, they will. It’s not really up to the professor or teacher if the student succeeds, it’s up to the student. Like you can bring a horse to water, but you can’t make it drink is what I’m trying to say. They’ll find out by themselves that by not paying attention to the lecture they’ll struggle in class. Like let people do what they want to do and their consequences will be their own.

Btw I’m grown and in college 😉. This is just a thought I have.