Why not just get your users to update their mail preferences to set 'warn me about blank message subjects'? Not sure if this can be controlled via policy now, but maybe this would be the best option. Global and/or local defaults.

I don't like giving Administrators the rights to control a feature that is basically a personal preference. Should I choose to send an e-mail without a subject that should be a matter between me and the receiver(s) and nobody else.

I hate those messages without a subject.

And I hate those messages where the sender kept an old subject, while the contents is something completely different.

Just enabling the warning will not be enough because all emails are required to have a subject as this is the preferred choice for a number of reasons...

Having this feature as a policy setting would allow an administrator to enable this feature for sites that prefer to have this restriction without having to touch the mail templates. As for sites that do not have/want this restriction, the setting can just be left disabled/not enabled.

Even with this feature, the administrator would still be able to allow authorized users the ability to send blank subject emails as long as management exempt them from the restriction by not applying the policy that has this feature enabled applied to these users. However, this is not a concern in our environment because this restriction applies to everyone.

@2 I concur. This is almost a solution searching for a problem.

@4 It seems like the process to implement this one checkbox would cause an entire new policy and settings architecture and create excessive group or exception-based policies to handle the one office of an office in a new division that wants the option to send mail with or without a subject.

@1 Has the idea to address what @4 proposed, imho