[AtlUmpSteve]

An additional explanation I was given (although specificly relative to football at the time) was that NFHS is concerned with extraneous anythings which might then be used to display gang colors or signs. In that case, the issue was the color of towels, which must be white without any markings. I think it is fair to assume the same policy has extended to wearing even rubber bands or cloth bands, unless it is considered to have a sport function (like a sweatband).