I know that some parents have a better grip on their children's behaviours and I always thought I would too, but we also have other issues with our son which has had to be considered at each turn.
They don't have a grip on their child's behaviour better than you.
They have children who haven't got issues that they are communicating through behaviour.
I work with children with SEMH. They come from all sorts of backgrounds with all sorts of parents.
Some have been model pupils for years and then suddenly change.
Believe me. Having concerns that no one will support your child after punishment to move onwards and upwards is a real fear parents have. I've experienced it myself which is why I went for this position and why I'm so passionate about it.
And why I butt heads with some of the school staff in some of the schools I do outreach for 
Most people in education are perfectly great at their job. I wouldn't do it for all the tea in China and I feel sorry for the teachers dealing with these pupils behaviour whilst trying to teach a class.
But I hate it when you meet a few who won't even try and meet a child and their family halfway and focus on the future and support and get stuck in the "but they did this".
I'm sure they've all done things they wish they hadn't and wouldn't want people defining them by it.