I found a short little article on it. Has pretty much the same info as hoosier posted.
http://2worksforyou.com/news/stories/underwear.shtml
Child disciplined for wearing Halloween costume to school
A Tulsa parent is outraged over how her child was disciplined at school for wearing a costume.
Crystal Harris says her 5-year old son was forced to take off his costume, and go through the entire school day with only his underwear on.
The incident happened Monday at Walt Disney Elementary.
School officials acknowledge they have a policy that forbids costumes, and that's why the teacher did what she did.
They say they've have apologized to the family.
Harris says however the teacher should be disciplined for embarassing her son.
Harris' son has not been back to school since the incident, and she says she's considering legal action.
Nov. 02, 2005