re: Parents beware:
While a criminal record might be a bit heavy handed...
Such meetings are often not just "parent-teacher" meetings any more, but "school based team meetings" and may involve the teacher, teaching assistant, principal, counsellor, psychologist, learning assistance teacher, behaviour specialist, etc, etc. A lot of school boards make it so that such meetings are invalid without parental participation, and if they don't show up, all these people have wasted a chunk of time, which is usually in short supply. Meeetings like this usually occur after school hours, too, so it is cutting into personal time.