Add a prefix to email notifications

Hello,
Within the Notification settings in the backend would it be possible to have a email subject prefix field? This can then be completed with a series of character etc that are then added to any email notification subject line.

We have had requests from forum users that being able to filter forum notifications within their email software would be very helpful, and having a prefix added to the email subject would allow them to setup smart filters on their email inboxes to handle all forum subscriptions separate to their other email.

Thanks