I agree that there seems to be a huge element of luck in the Oxbridge process, and that selection is a bit of a mystery - but that also mirrors life, thinking about applying for jobs for example, where there is definitely luck involved and the choice of one candidate over a field of similarly qualified and experienced candidates is quite mysterious. :)
Good luck to the dc of everyone who still has an interview or two to go! Dd had her final interview at O yesterday and is now just relieved to be doing boring stuff like history coursework and some revision for mocks in January. She was lucky enough not to get the silent treatment in any of her interviews, but says she had a very strong feeling in all of them that the interviewers were disappointed with her answers, and she never really felt that she was engaging in a dialogue with them. She'll be looking more closely at the unis which have given her offers after mocks are over, and would ideally like to visit them (she didn't apply to Durham for some reason).