Though I could agree to a point, I feel that this is a fundamentally poor argument. This could maybe be the case (and most likely a stretch) if a band got say 20th in marching instead of 25th, but it is very hard to argue the top groups in terms of how they look visually.
Also, something that I think many fail to realize is the main reason for having props: giving the members that did not get a marching spot an important role in the show. As a program, you have a better chance at retaining members if you give them something to do and let them know that they are an important part of the organization, rather than cast them out because they did not get a marching spot. Marcus has over 300 members, and considering the numbers they march, that would leave out a good amount of student involvement.