Yes.
The Iowa Court of Appeals several months ago heard arguments in a case involving a 17 year old student who drank beer in Germany (where the legal age to drink beer is 16) while on a summertime trip arranged by the school district, approved by the board, and chaperoned by a high school teacher. All participating students were informed before they left on the trip that if any of them drank beer or alcohol while in Germany, they would be punished under the district's good conduct rule. The Court of Appeals held that the district's good conduct rule applied to conduct that occurred in the summer, outside the state (and country, for that matter), and was otherwise legal. Finally, as this was the student's third violation, the Court ruled that it was not unreasonable that his punishment was a 12 month suspension from all extracurricular activities. Martin v. Marshalltown Community School District, #00-154 (Iowa App. 2000), 2001WL293237.