A couple demos is a small price to pay for a 98. Good on her for keeping her priorities straight.
One of the simple joys of a military education is that you have way too much to do in way too little time. They plan it that way to force you to learn how to prioritize things. At VMI, you have to roll your hay (mattress) and put your wooden rack up against the wall every morning before formation. If you put it down again before noon and you get caught, it's 5 demerits. If you don't get caught, it was just a good nap.
As demonstrated by the Battle of Guilford Courthouse, sometimes you have to concede the battle in order to win the war. You can either take the 5 demos for the unauthorized haydown while catching 20 mins extra sleep, or you can skip the demos and then sleep through class and miss information that will be on your test next Tuesday. Sometimes you just need to eat the demos and not worry about it.
Yes, demos add up and will eventually you into all kinds of trouble, but generally not as quickly as failing your classes will.