I see the filming in the same vein as 'in the public interest' for newspaper publication.
Filming teachers is a no no. Unless something is happening that is in the interests of whistle blowing and public interest.
Thus I also see comments attacking Murray for filming in this context of being a whistle-blower.
It is true we do not know the whole story with this case. However it raises so bloody big questions about human rights - and freedom of thought is a human right. Without the video there is no way we could ask further questions as to context as the kid would simply be called a liar because he is the one without the power in this dynamic.
It could have a backstory which isn't so nice, but this still does not mean we should be gaslighting kids in this way. They have a right to reality.