I’ve recently stumbled on a bug in Outlook 2007. Apparently it is quite well known and the only reason that I hadn’t found it was that I don’t use Outlook as my main email client. In fact I only use email on it to handle meeting requests. The bug is that Outlook 2007 ignores the setting regarding sending reply requests for IMAP accounts. If this seems rather irrellivant to you, you might want to think again.