Research has shown that heavy AA can lead to a mismatch between the putative beneficiaries and their peers. As a result, these students are more likely to end up in the bottom of their class (IIRC, 50% of black students at top law schools ended up in the bottom 10% of their class, and AA beneficiaries who planned to major in STEM were more likely to change to a non-STEM major).
So it is also possible that a preference that helps your kids get into a school could actually end up hurting them if they end up outmatched by their classmates.