Even though you are scored, I do believe that it is not. My reason for stating this is because Marching band is a class you take there fore you get a grade for the school. You don't get a grade for football.
Yes even though that it is a class you have to take it because you have to have extra practice time. I for one am I band student and yes we do have to take a "band class" we mostly get graded on the outside school performance, not weather of not I'm in class that day or not
Just because you get graded on the outside school performance doesn't mean it is one. Now referring back to your comment about Lacrosse, all you do in marching band is walk in a ordered formation in lacrosse there is running and smashing into each other. A lot of people in marching are not in the most best physical condition. in regular sports you have to be in really good shape.
In marching band there is a thing called DCI ( drum core international) and in DCI it involves having to be in the best shape, contributing your life to it and basically traveling 24/7 with your drum core. When you are in dci you have to run everyday they control your meals and when you said that lacrosse involves running so does marching band, a lot of the times you have to basically sprint to your correct spots and sometimes depending on your instrument you have to do it carrying a 25 to 75 pound drum or tuba. I would like to see a football player sprint the whole field wearing a 75 pound drum and not snapping the harness or the drum