$block: the Block object that was saved
$user: the user who did the block (not the one being blocked)
+'EmailConfirmed': When checking that the user's email address is "confirmed"
+$user: User being checked
+$confirmed: Whether or not the email address is confirmed
+This runs before the other checks, such as anonymity and the real check; return
+true to allow those checks to occur, and false if checking is done.
+
'EmailUser': before sending email from one user to another
$to: address of receiving user
$from: address of sending user