Outlook: reduce mails during holidays and longer out off office periods; sender gets back the e-mail.
When on holiday or during longer out of office periods Outlook-inboxes become overcrowded. Back at work there is a lot of work, just opening those e-mails. Very often you don't need to react anymore.
Outlook automatic answers tell senders what is the reason of absence and give indications about when you are present again.
E-mail-senders notice only that there will be an out of office reply, but can't see what's the reason and the period of out of office. This is too little information for helping you to decide sending the massage or not.
My suggestions: when making an out of office reply add the possibility: 'sender gets back the mail' with the out of office tekst of reciever. For the sender add the possibility to decide, after reading the out of office text, to send the e-mail of not. He/She can decide based on the information of the out of office reply instead to decide just as a reaction on the simple sign: 'There will be an automatic answer'.