No. If 90% of students attended the same school as their parents did, that is one thing, but I don’t think they do.
Plenty of students have no interest in attending their parent’s alma mater. Others apply to make a parent happy and because they don’t HATE the school, but it is nowhere near the top of the list.
It would be a huge assumption to conclude the student applied as a legacy in the first place and another to conclude they would automatically prefer the legacy school. I don’t think AOs engage in guessing games like that and I doubt the data would show other school legacies to be a yield risk. (It would be interesting to see the numbers.)