Legacies who don't apply EA

My son is starting the college application process. He is a Princeton legacy but we are not interested in pushing him to go there. Which raises the question of whether legacies get benefits in admission if they don’t apply early action/early decision. I understand that some schools are known for providing benefits to legacy applicants only if they apply ED (Penn and Northwestern come to mind), and other posts on this site say that an admissions officer at Yale asserted that there the treatment was the same for legacies between SCEA and RD. Is there any wisdom about whether the same is true for other SCEA schools like Princeton?

The legacy admit rate is around 30% overall and to my knowledge there is nothing Princeton has indicated directly about when those admits applied. I am guessing there would be strong preference for those legacies who apply early as an indicator they are more likely to accept an offer of admission than those who apply in the RD round.