[wmaiouiru]

I wonder if kids in NYC are also taking trains to school like kids in Tokyo. On a separate note, growing up in Japan, the concept of renrakumou (telephone contact graph) was quite interesting. When there is something important from school announcement, people on this graph would traverse down the tree and contact the node to spread the word. http://oshirase.x0.com/jpg/templtes/renrakumou.jpg

[superuser2]

These graphs were a staple of emergency procedures in the pre-Internet era. Still are in some places. My mom was a teacher; this is how school closings worked.

[SamReidHughes]

That's something schools and organizations (such as high school marching bands) used for announcements in America, too.