dd1 is 14 and now is in the end of year 8 (year 9 in the UK) at school. In the parents teacher conference, some of her teachers have reflected to me that her attentiveness in class can be improved.
I have talked to dd1 about this, and she told me that since at her school the year 7s and year 8s use the same textbook and are accessed on the same things, just at different levels, she already knew everything from last year for some lessons, so she just joins in the classmates who are messing around (quietly).
I feel conflicted about this as I value a good attitude in class and to learning, but I also see little harm in her not paying attention as long as she is on top of things and does not disrupt class.