As for gaming the system, I am pretty offended by the suggestion that it was easier for me to get my place at Cambridge because I went to a school on the 'disadvantage' list.
Well it depends on your definition of “easier”. Cambridge does have a “distance travelled” part of their scoring system. The subject I knew about (note - this is very old) had up to two marks available for this out of the total 24 that you were scored out of. I suspect I got both marks there (I was state educated all the way through plus I was female and applying for a very very male dominated subject) and it is quite possible (even likely) that those two marks made the difference between me getting in or not.
But that doesn’t make it “easier”. Because that is the whole reason Cambridge has the “distance travelled” thing - to get the grades I got in the state system is so much harder than it would have been in the private system.
Re: gaming the system. The school I went to was the only state one in the town I lived in and had an attached sixth form. However, the sixth form was on a different site (two miles away) and you needed 4 As - Cs to get in so was very different from the true comprehensive that the main school was.
Roughly half the kids at the sixth form were “long timers” who had gone to the main school and half were from “outside”. Which with the school being the only one in the town meant from the local private schools.
How much the private school kids were influenced by the lack of uniform, mixed sex, separate site part and how much it was their parents who were interested in gaining “state school points” I don’t know. But I can see the attraction for parents. And it was obviously great for me as a very able “long timer” - losing Kenny Thomas and gaining Arabella was brilliant!
Most of them did seem to make a lot of “use” of the mixed sex fact of the school though whether their parents meant them to or not. 