Yes, I'm absolutely serious about this.
Cell phones are not permitted in my English classroom.
Ideally, students will not bring them to the classroom at all. Of course, we do not live in an ideal world. Apart from preferably leaving them in their locker, students will be asked to book their phones into the cellphone hotel in our classroom.
Each student needs to put their cellphone in their designated pocket (alphabetical order) - this is how I will be taking attendance.