The school I coach at will not allow the cheerleaders to wear their uniforms (shell or skirt) to school. I totally agree with this because I don't want a frantic text or phone call saying there's been soda spilt on the uniform, pen exploded, or heaven forbid blood. (accidents happen) Their reasoning is that they don't follow dress code. The skirts aren't long enough according to dress code (although they are longer than most other teams in the area, not too long, they look nice, classy, not trashy).
My high school I went to ran into a dress code issue. The uniforms we had (had for 2 years before the issue arose) showed about 2" of skin in the back and on the sides before it came down into a V in the front. For football we would wear the cropped bodyliners cause most the time it was still warm, for basketball the full bodyliners cause it was cold. They decided that they violated the school dress code and we could no longer wear them. We had to wear these one piece (yes one piece) uniforms for the rest of the year. Many of us went to the school and complained as the volleyball uniforms violated dress code as well since they were short spandex shorts (no different than our spankies we were UNDER our uniform). Finally, they decided that dress code didn't apply to school uniforms as long as no stomach was showing during play. Thankfully we bought new uniforms the following year and volleyball had to buy longer tops so their stomach didn't show as well.
Our AD, at the school I coach at, has actually asked other teams cheerleaders to put on warmup pants under their uniform or change completely due to their skirt (when standing at rest) not covering their butt or their stomachs showing. Doesn't make her real popular but it's not cute to have your skirt hit the middle of your butt when you are just standing there, it's tastless. I don't understand why a coach would allow it, why a cheerleader would want that, or why the school doesn't say something. One team in particular received a penalty at competition for their skirts not covering their butts.