A small point- and be prepared for the howls of outrage- why should it concern the OP? Well, it all depends whether the school is claiming charity status or not, really. If it is, it could legitimately be seen to be other people's business, too.
FWIW I know someone who has 2 DSs at an expensive prep. DH works for a bank that is now 80% state owned in the sort of position that earns the sort of bonus that pays enough to send 2 x DS to a school that charges £11K pa per child.
What pees ME off is the fact that it COULD be said he's been able to fund his DS's far more privileged education on the back of what transpires to be other peoples misery.... I mean, to the extent that there may well yet be legal action regarding the behaviour of this bank! And he is by no means alone.
YET the DW, whilst terrified DH's job may disappear up the swanny, not completely unlikely!- is SURE the school will fund the DSs ongoing education- in Y6 and 4! I was initially rather annoyed at that possibility but now I realise there's little chance of that happening. You may say I'm gloating- we-e-ell, I've had the piss taken out of me on numerous occasions about how I worry my pretty little head about which state option to go for for MY DSs,- ha, IMAGINE having to think about class sizes!- because she's so convinced she's in the clear!
The next issue is the hardship one based on 'why should something going wrong within the family cause the poor DCs to have to change school? It's SO unfair to disrupt them!'. This can range from bereavement to redundancy (such as if your wild risk-taking with other people's money causes the bank you work for to go cap in hand to the government?!). These are obviously 2 ends of a spectrum. Yes, I believe it IS OK for a school (with charity status- it's ENTIRELY up to a proper 'private' school to do what it wants with its money!) to see the bereaved DCs through to perhaps the end of the next stage of their schooling. But redundancy? It's almost as if 'How COULD you penalise THE CHILDREN of someone down on their luck (and place them back amongst the other 93% of us! Ugh.)?', Well, how about the penalisation that could be said to go on all the time to anyone who CAN'T afford a posh, privileged education for their child where their 'C's will be turned into 'A's, their accent polished to cut glass, their 'contact list' bullet proof?
Cuts both ways!