Of course the GOTV effort was only in heavily Democratic areas, so if the impact is partisan even if the leaflets might not be. When I was kid we learned about the Democracy by having mock campaigns and elections within the school. What's wrong with that?
There's nothing wrong with mock elections and campaigns within the school.
There's something very wrong when you have public school students, on public school time, working for an organization that has endorsed one candidate (kerry in this case) helping that organization get out the vote.
It's like the teachers were providing volunteers for a pro-kerry group on the taxpayer's dime.