I think it's also a function of class size and class year, as well as students really understanding the dangers and social mistakes of keeping that laptop lid open. For me, as a mature student, I treat the laptop lid as something I can open before class, or during class to Google subjects related to what's being presented, or see something in more detail and add it to a "For Later" list in Safari. I choose to sit up front so I'm not personally distracted by others watching movies, and I actually close the lid and/or look at the prof to make sure he knows that I'm paying attention. In many ways I feel like this is just missing etiquette training, students not taking things seriously because they're still outgrowing their high school antics. Ultimately, the computer is a tool for learning, just as the classroom auditorium is. I wonder how this discussion would change if the learning was delivered online? Would there instead be directions on how to disable notification bars on your phone, set up auto-replies to texts and chats and recontextualizing computers as the learning tools they can be? Or without the auditorium would these issues go unnoticed?