My 2021 DS is in Band Co and says they have plenty of varsity athletes in Band. As @kpmom2013 said, the biggest commitment will be for Beat Retreat. The school instruments are pretty much POSs, especially the trumpets. Both my DSs took their trumpets to Indoc and kept them in a locker until needed. No problem there. If you're a decent trumpeter, there will be additional opportunities to play - taps, ceremonial events, and even the Trumpet Fanfare, which uses school-supplied herald trumpets.
Did your DS's take there primary "good" trumpets to Indoc or older beat up ones? Isn't that a lot for them to carry at Indoc where I read it was important to pack light?
Well some believe athletics is as important and equal to the academics. And it really is not reasonable to disregard those individual drives. If athletics is important then you should embrace it. Not ignore that drive and ability. After all that drive is what got you to KP in the first place. No matter what some may say.