They are mostly harmless and if one makes sure that they report, there is practically no problem with them. They do what they have to do, and if they don't, they ignore me quietly and unententively. If I have learned anything from my PU, I can keep running among the students and check if they work as they should and if it is clear to them what to do. Although I sincerely hated it as a student (especially during the papers), as a teacher, I understand that this control has its own benefits.
If I have learned anything from my PU, I can keep running among the students and check if they work as they should and if it is clear to them what to do.