On Monday, at Conrad High School in Missoula, Montana, Principal Raymond DeBruycker spent the day looking after a dozen horses ridden by students to school. According to a post by the school on Facebook, "Montana has an old law saying if a student rides their horse to school, the school principal has to feed and tend to the horse throughout the day."
Apparently, Montana high schoolers commonly pull this prank at the end of the year. If you can point to the actual law in the Montana Code that they're flaunting, please do so in the comments.
Meanwhile, from a 1992 report titled "Montana's School Transportation Policies and Funding:
Horse stables and hitching posts were common on school sites well into the 20th century and were maintained at some Montana rural schools into the 1960s. The first 'buses' provided by school districts were horse-driven and required maintenance of a horse barn on school property. Until the 1971 recodification of school law, the definition of "nearest practical route" to school, used to determine individual reimbursement, included horse and buggy tracks.