Blocked users have taken to spamming dozens and possibly hundreds of admins,
requesting to be unblocked. While this has always been true to some extent,
lately it has been happening with increasing frequency. It generates a great
deal of confusion for admins (to get emails from users they have had no contact
with, asking to be unblocked), and the blocking admin receives dozens of
messages from other admins asking why he blocked a particular user.
At block time, a blocking admin should have the option of disabling the blocked
user's ability to send emails through the email-this-user function. More
importantly, Mediawiki should also have a throttle setting, (so that the feature
cannot be used more than X times per hour, for example). This won't stop the
abuse, but it will make it significantly more difficult.