I'd like to reopen this for discussion, as I had a client recently ask if this is at all possible. 

Original Description:

I think for an enhancement to the messaging system in Moodle we should include a Auto-Reply type notice to pop-up. If I was to put this pop up on my messages settings then automatically this will appear to any user trying to message me, thus avoiding the hassle of them trying to get a quick response and they are aware of when I am away and will return. The reason I am asking is because at our institute we have teachers that sometimes go away perhaps for a week and they need a way to show all there students they aren't available for questions and for marking assessments. We use the message system within moodle for our communications so this would be a great addition.