Agreed - and the richer ones are more likely to be able to pay for - or quite possibly already paying for - private tuition. I think it is openly accepted by people in education around where we live that the "results" of the so-called best schools are bolstered by people paying for private tuition.
I have some sympathy with the "seeing other cultures, hearing other languages" sort of comment, BUT at the end of the day the school has to deal with this thing called the National Curriculum, and what kids do on holiday will not be in tune with the national curriculum. People who are not...