I thought of you when I noticed the same thing. And then sent a reply;

"Not that I care too much myself, but you may want to use the wonder that is BCC when sending out these mass emails. Just in case there are a few who would rather keep their primary email somewhat private."

I love how their reply had absolutely nothing to do with the issue addressed;

"Sorry, but we are trying to reach the entire class and the only way we can find everyone is if people send us emails of their friends that we don't have already. Just trying to contact everyone we possibly can...it is taking forever to track everyone own."

Their assumption is that there will be a cadre of people who give enough of a shit to go through the entire mailing list, presumably with yearbook in hand, looking for the people they know who are missing. Just know this Josh, I sent that for you baby, for you...