I don't know why LessHeard developed his email caveat, but I do have my own puzzlement. I see a paradox in the confidentiality of email. If the guy says 'Please unblock me,' and the admin who gets the message wants to discuss that on the wiki, how can he do so?  Is he supposed to keep it secret that the guy wants to be unblocked?  Or, does confidentiality prevent him from forwarding that mail to another admin to get a second opinion?  

I suppose there is no perfect way to fix this without a written policy, and that would be instruction creep.  Individual admins could create their own caveats. I hope they don't pick the version chosen by LessHeard because we should be able to be more sympathetic than that.