There are just too many flavors of this, so let’s organize it, roughly in order from least available to most:
Type A1: I am off the internet. Don’t even call or text me.
Type A2: I am off the internet, but in a tremendous, time-sensitive emergency, you can text or call me.*
Type B1: I will have spotty internet access, but don’t intend to use it.
Type B2: I will have spotty internet access, but don’t intend to use it. In a time-sensitive emergency, you can text or call me.*
Type C: I will be reluctantly checking email from time to time, but don’t count on a response unless it’s an emergency. I’m on vacation!
Type D: I’m traveling for work, so getting to email will be difficult. I will get back to you as soon as I can.
Type E: I’m in meetings all day, so getting to email will be difficult. I will get back to you as soon as I can.
Type F: I’m getting ready for a long vacation or work trip. Though I’m still working for a day or two before I leave, I am scrambling to finish up high-priority items. I may not get to your email until after I return.
Type G: I’m just overwhelmed right now with a time-sensitive project and need to focus. Probably this time-hoarding anxiety will pass sooner than I think. I will get to your email then.
I think types F and G (especially F) are often overlooked as auto-responses. Instead, we tend to just ignore stuff. We could at least communicate why.
* Obviously only applies to people with my number.