Is there a way to prevent our users from sending messages
that are lacking a subject line?
Here's how I prevent myself from sending such messages:
Private Sub Application_ItemSend(ByVal Item As Object, _
Cancel As Boolean)
If Item.Subject = "" Then
If MsgBox("No Subject: line!" & vbCr & vbCr & _
"Do you want to send this message?", _
vbYesNo + vbExclamation, "Confirm File Send") <> vbYes Then
Cancel = True ' cancel send
End If
End If
End Sub
I suppose you could install the above on every user's machine.
However, you will then have the problem of macro security prompts, so
you better sign the macro.