Don't see how.
Once again the difference is a more level playing field.
Say for example in champs Johnny scores 2 tries in a one sided game and his opponent never touches the ball, how can a fair comparison be made? At least in zone this scenario is less likely to occur.
And greater transparency, ie selection criteria is known to all, makes it difficult to stack a side with favorites if the performance is not there.
Don't see why this is a problem for some.
But the little Johnny who doesn't touch the ball in your scenario won't even get to the zone trials.
I'd add, that if a boy doesn't touch the ball, he's probably not looking for it in the first place.
But you see, in your example, you highlighted how the selectors got it wrong at the zone trials anyway.
Your 2nd point was that zone games are at the same ground in the same conditions, so are the state championships - so that argument doesn't hold any water at all.
One off games at carnivals aren't a particularly good way to be selecting teams. What should happen is that after the State Championships a train-on squad of 40-50 boys are picked and they attend training sessions for skills evaluations and development and play some internal trials to pick the final team of 23.
Finally, if you think it is possible to have a selection process where nobody has any favourites or pre-conceived ideas, I think that you are going to be disappointed.
