When it comes time to enroll in college, I want that savant to go to the best music secondary school that they want to attend. I don't care whether they were "born with it" or "earned it", but I do care that they demonstrate outstanding ability.
Not "outstanding ability, after considering factors X, Y, and Z", but simply "outstanding ability".
What is "the best school" here? It must be "the school that will best develop their particular talents", right?
Presumably you want them to go to that school so they can produce the best music possible with their abilities, for the benefit of society. The other option I see is that you might want them to go to that school because they have "earned it", but this is silly, especially considering a case where they haven't done anything, and are just naturally talented!
You now have two problems- first, one school might be excellent at training good musicians but not so great at training savants. Second...
Suppose you have one spot in a magical "savant school", which is able to develop somebody's skills better than anywhere else in the world. You'd want to assign the student who would benefit most to this spot- the one who has greatest potential.
This is NOT the student who currently writes the best music- this is the one who will write the best music after attending the school.
You don't care about ability now- you care about ability later. Predicting the latter from the former alone has an obvious flaw- training and practice improve ability.
Because of this, it's a good idea to consider measures of how much training somebody has had, in addition to their current ability, for admissions decisions.
Unfortunately, quantifying that is hard- so other metrics are used as proxies. In considering admission to an Olympic swimmer training program, for example, perhaps one might consider how early somebody learned to swim, or how often they visited a swimming pool.
The best music school here is the one that they wish to attend. They (and those who advise them) are in a far better position to evaluate the variety of factors that influence that decision than I am, as someone whose only musical instrument ability is a CD player or iPod.
Some music savants want to attend a music school that the composer or musician they most admire attended, others the one that is closest to home.
I don't understand why one would want a talented student to get preferential admission to a school because, for example, he liked the design of the campus. I only get the argument that a talented student should get admitted to a school that'll best develop those talents. The link between "you're talented" and "...so you should get to go to any school you want!" is one I don't get.
Why doesn't that lead to absurdities like a school which specifically excels at teaching "low-talent" students, churning out competent (if unexceptional) composers, still admitting talented students preferentially?
And if the savant kid happened to only see a musical instrument for the first time at 10 years old, so that when they took their music entrance exams at 11 years old their performance was very good but not quite at the same level as the other kids who had been learning for 10 years, you would just want to assess all of them on performance at that moment, and choose the kids that had been playing longer because your objective assessment is that they are better musicians.
Not "outstanding ability, after considering factors X, Y, and Z", but simply "outstanding ability".