When it really comes down to it, jeans are probably the best thing for a young lady to be wearing when she is paddled at school. There really is not another clothing option that offers as much padding as denim. Certainly, the way young ladies wear their jean today, which are ultra-tight, does not help as much as baggie pants, but it still offers more protection than thin cotton pants, or even worse, a thin little skirt.
There are those unfortunate young ladies who are sent to the office and end up getting paddled wearing a light skirt, which does so very little in protecting her bottom. It may be that she is a girl who has conservative parents that make her wear a skirt to school every day. There are also those occasions at school in which formal attire is required, such as a drama production or a choir performance. While the skirt tends to be conservative dress, as it may go all the way to the ground, the material is very thin and there is not much between the paddle and the skin.
Many young ladies in recent years often go without panties, especially when wearing something that is full length. You really cannot get much closer to a bare bottom paddling in school than for a paddling to be administered only over a formal summer type dress. There is no doubt real lessons are learned in the school when a teen girl is paddled over her skirt.