SheCutOffTheirTails - you said:
"They are getting a subsidised room rate, and free marketing opportunities to a captive (and impressionable) market.
No private company should be getting those things unless they are offering subsidised places."
Can I clarify - are you talking about the OP's school, and if so, where has she said that the club is getting a subsidised room rate for hire of the school premises (I've looked and can't find it, but am more than happy to be shown if I have missed it)? It may also be that the club's prices have already been reduced, if the club is getting a subsidised rate, so it is being offered to the children at a lower rate than it would be if it were in other premises.
TBH, whilst I agree that if a club is getting a subsidised room rate, it should offer subsidised places, I don't see how an individual club could tailor those rates to the financial circumstances of the individual children/families - they'd have to have access to some pretty personal information.
I also believe that it is perfectly possible to explain to children that different people can afford different things, without attaching a value judgement to that (as you said to Jenai, "Maybe you are fine with your children being brought up as entitled brats who learn early that poor children are fucked in terms if opportunities. I'd prefer mine were a little older before learning that lesson."). My dses have grown up knowing that we can afford more things than some of their friends' parents, and less than others, and that has at no time translated into a judgement of the people concerned.
I'd also argue that it could be a good thing for children to understand that there are people worse off than themselves (not, you note, that there are people who are intrinsically worse than them), because that enables you to discuss the importance of finding ways of leveling out those inequalities, and to show your kids that they can do things to help their friends who are less well-off. For example, if child A gets sent to football club, he can teach his friend, child B, the skills that he is taught at the club (not, before you accuse me of it, in a patronising the poor way, but in a friendly way).