This is my $0.02 worth on the recent case where a school did not let a student talk to his mom in Iraq (http://www.mudvillegazette.com/archives/002772.html).
In terms of how the school handled it, there is so much :he said, she said" that none of us will probably ever know what actually happened. But I can understand a 17 year old getting very upset if it was his one chance in a month to talk to his mom, who is in a war zone, and the call was ended. It would take a rare person to not get very upset very fast in that situation. So I would say his reaction while possibly not correct, was very understandable.
Second, all of the blogs on this state that calls come from Iraq about once a month. We have the most advanced telecommunications system in the world. The military has tremendous bandwidth between the U.S. and Iraq. Why do they not have it set up so people can call home daily - and for free? This seems like a very easy and cheap way to improve morale.
Finally, schools should have a very simple rule for calls from Iraq (at least as long as they remain a rare occurance). If a student gets a call from a close family member from Iraq, they are excused from anything - immediately. However, the school administration has the right to check any call by speaking to the person on the other end. If it's not a call from Iraq, then the student loses their rights to take calls from Iraq. No student is going to risk losing the right to hear from their parent by faking who the call is from.