I'm all for balance but I couldn't imagine trying to coach a high school sport with only 1 1/2 hours/day for practice. Having the class helps too but even so, that is really a short practice time. Most sports here work out fine with marching band-the only exceptions are volleyball and that is because they have tournaments every Saturday and the band has competitions every Saturday so you would have to miss too much of one to do the other and girls soccer because the soccer coach won't let the kids be in marching band. We even have football players in the marching band, they just march the half-time show in their football pants and band uniform top.
Football and Volleyball are the two sports which don't work with marching band, practices & games conflict. For the rest, the coaches and the directors pretty much work together, providing the student has room for both band and their sport in their schedule.
Just my limited observation based on our experiences over how fanatical Texas is about sports, I can't imagine what life would be like if our governing body didn't have these limits in place and I think my family's life is pretty crazy now!!!