There ought to be a word - and perhaps there is, in German - for the mix of feelings that accompanies composing and activating a holiday out-of-office message. There's smugness, of course, and a gratifying sense of laying down one's virtual tools after a horribly long shift. But for many of us, these nice feelings are tempered by the knowledge that in two weeks, refreshed but depressed, we will have to trawl through hundreds of emails, many of which will be conference room notifications for meetings about crises that have passed.
This would go over like a lead balloon at my company, and, were that person on my team, I’d tell them to change it. It does have a connotation of “when I feel like it” about it, and most of my team is not high enough up the food chain to take that sort of stance (and the ones who are high enough up are client-facing and have the good sense not to do so).

I will return with a glowing tan on [insert date] and respond promptly to all emails. If your request is time sensitive, please email [insert name] at [insert email].
So, skip saying you are in Las Vegas attending your favorite conference with the hopes of seeing a show or finding some time to play the slot machines. Even if other colleagues are going to the same conference, just say you will have limited email accessibility for the week and will return the message as soon as possible. Rather than an Instagram post with the view outside your window and naming the hotel as soon as you arrive, save the photos for a limited audience upon your return. Finally, consider adjusting your settings so that your out of office message is sent to contacts only.