I am pretty lenient with what my kids see but it bristles with me that their school just makes them watch 2 hour length PG rated films without first checking whether we mind about the content. My DD (year 3) watched Arthur Christmas today and whilst I don't mind her watching this, I would imagine some stricter parents would object to the alcohol and sex references. When my DD was in Reception, they watched a U rated film which whilst it was a 'U' still left some of the class in tears. Another one they watched on a previous year was Nanny McPhee (don't know if it was 1 or 2) and I recall there was mild swearing in it.
Firstly - why can't schools just show something for an hour rather than 2 hours - surely that's a home treat prerogative for the parents to manage? Secondly, if they must show a long film why can't it be a U rating?
If I take my DD's friends out with her to the cinema, I take pains to tell the friends' parents I will be taking them to a U rated film because I am wary of other parents' levels of strictness about film watching - (my dd is 7).