University Admissions is not an exact science.
And when I read on the MN HE forum and some of the posts (not necessarily just on this thread) with people seeing if they can game the system, you might see why from the applicant's side!
But whatever parents & applicants like to think, most - all, really - staff involved in university admissions - both professional administrators & academics - are not in some dark sinister plot to admit unfairly.
We want the best fit for our courses! I don't want to be teaching someone for 3 or 4 years who doesn't want to be there, or for whom it was a forced choice, or who can't quite manage the level of study. Or who thought they'd come to my place for reasons other than they felt it would be the best fit for them, now, and help them towards making the life they want.
We have 3 to 4 years of human interactions with our students. We want hm to be willing, mostly happy, and mostly confident about their course (no-one can be happy & confident all the time!)
5As I often say to my graduating 3rd years, some of whom who get caught in the paralysis of what to do next (I know that feeling - I had it big time on graduation) eventually you'll get to where you need to be, but probably not by the route you expected.
So I hope PPs can be confident that there is no favouritism, no unfair advantage (well, apart from the socio-economic advantage that is beyond the control of Admissions Tutors), and that most universities want to "level up" - we want to find the best & brightest, and most élite universities will do a lot of things to make sure we look for potential students in previously overlooked places. In my department, throughout the summer, our seminar rooms & other spaces are full of summer school pupils, often from the poorest postcodes in my region, trying to give them a feel for a supposedly 'posh' university ie a Russell Group/research-led high achieving place. Taking the mystery out of studying at university and trying to provide opportunities for all.
I really wish parents wouldn't overthink the admissions process as if universities are out to cheat your DC. We are not - quite the reverse.