Hmmm, this is a hard one to answer, because it is usually the other way around: more typically, a kid auditioning for a BFA can find out that she got into the university as a whole (academically) but not into the BFA. (I know at least one person posted a few years back that this happened to her with Penn State University's musical theater program: she got a fat envelope, but inside, it said she could enroll in another program, like nursing, but had not been accepted into Musical Theatre.)
At places such as NYU-Tisch, if you don't get in, you don't really know if it is because they didn't like your audition or because your grades were not up to par. The process there is not bifurcated in a way that is transparent: you just know if you got in or not and not why.
I do remember attending the Boston University BFA audition with my kid and Paolo (the guy heading up the info session and auditions) telling kids that they needed a 2.0 GPA or better to get in (not to mention a smashing audition!) and that if you had less than a 2.0, he couldn't help you, even if you were brilliant as an actor.
A few years ago, I heard about a ridiculously talented kid who got into Minnesota-Guthrie via audition but the university wouldn't accept him because of his grades. Since then, U of Minnesota has changed the way things are done, and candidates for the BFA have to be accepted into the university before auditioning (I believe. That's how my daughter did it, anyway.) So again, with Minnesota-Guthrie, you would know already that you had been accepted to the university and if you didn't get offered a spot in the BFA, you could still attend the school.