> Shouldn't sendmail do this if it's running as sendmail -bd -q30m ?
> (try to de-queue mails every 30 minutes)

Yes, but sendmail isn't turned on in the default /etc/netstart.  At
MIT, we don't turn on sendmail on our client machines, since all
incoming mail comes through the mail hubs.

It does seem like a shame to have such a cron job when many mail users
are just going to turn on the sendmail daemon, but the current
situation seems patently incorrect.