My dc have attended many independent schools as we travel due to work contracts.
Many schools will never experience these conflicts of interests (The lucky ones).
In highly selective schools this is absolutely a thing. At the end of the day, all parents are pushing their own children for university resume or life opportunities. The very reason they’re there. Amongst staff and the children of staff this nepotism and cronyism is unfortunately incredibly common place. They’re (staff) mostly all friends and sympathetic to each others struggle (even with fee remissions) .
You must follow the schools complaints procedure it will be readily available on their website. Complaints to administration (friends) often falls on deaf ears. We completed it, polite mention to teacher, head (to cover ourselves) response will be the standard gaslighting. Your perspective is wrong. Insisting! we were still not satisfied and our recollection differed to staff, we then contacted the governors (where there should be some form of impartiality).
Many parents had quietly collected evidence dates, examples and notably after that exposure we found the lions share of opportunities did not continue to go to that same one or two children. Staff were now aware they were being watched and closely monitored.
Our main argument was “how do you expect any of our children to develop, to achieve if it’s only the same children receiving the fixture invitations or coaching (actual sports coach not just math teacher filling in)?”
Some schools (mostly where there is no conflict of interest within the year group) will never experience this. However, it is rife within selective independents and very poor taste. Staff want the sports roles for their own kids school records.
It seems universities today (all too aware of the corrupt practices of independent schools, old boys) aware the influence independent schools once had to play such underhand games is rapidly eroding.
For independent schools, its ring fencing opportunities for their own (staff) gain ahead of full fee paying parents. The pastoral breach in any school where this is common place should of course be investigated fully by any governing body. You’re right it deeply impacts child moral and well being. Not at all what any parent signs up for. Common sense to the impartial ear.