We whole take on that issue is that it just happens. Deal with it. If they signed a form saying that their diplomas would be withheld if their families cheered, it's their fault.
I never liked cheering during graduation. It makes you feel less important if your not the most popular, or have the most people there. I didn't like it when people would cheer more for some and not others. It makes you feel insignificant, when everyone should feel equal, because everyone is graduating. Your a class, not just an individual.