Not a teacher, but yes. The very same app that teachers use for grading, is my guess. The teacher does the attendance tracking. The app just records what the te

Not a teacher, but yes. The very same app that teachers use for grading, is my guess. The teacher does the attendance tracking. The app just records what the teacher puts into it. The teacher is free to take notes of when people leave and enter. If most of the class time has the students seated then a student walking around likely is very eyecatching. (What do blind teachers do? Roll call + the honor system is my first guess. Maybe handing out bathroom passes manually would be a viable Plan B.)