Unfortunately or unfortunately, we live in a different time. When I was a cadet, no smartphone, so texting was not an issue. The question is about complying with the system vs. doing something new. I think these are different mind set, not necessarily good or bad, rather why not. The common sense says, a cadet shouldn't text while "marching," but is there an actual regulation that prohibits texting while marching? Or what can USMA do to me while I am a few hours away from the graduation. Personally, carrying shoes while marching looks very unprofessional, but it might be practical to for whatever purposes.
I guess the future belongs to the new generation, so they can make their own rules and also accept the consequences of their new rules.