Actually schools represent our biggest customer base; although our B2B is the highest traffic on a daily basis. Most schools use it to announce all manner of things that are coming up (including several emergency lock downs). However, it is weather closings that really stress the system. Several geographically centered locations all hammering their full list at the same time. All of these calls will terminate into the same exchanges.
It is strange to see the system spike, investigate it and find that a nearby school has just be locked down because of a gunman on campus grounds. The supers can sound surprisingly calm when informing the parents not to be alarmed that someone with a gun is on campus and they have everything under control.
I understand the hatred towards robo-calling, but there are many legitimate uses as well. At the end of the day I do not feel sleazy about my code, or my company, because our system is emergency and B2B based. We do not do UCEs.