We are encouraged to put up messages that say we have “limited access to email” and alternative contact for things like travel between offices and conferences. We’re technically working those days, but it may be hard to reach us.
Proof that some people just Don’t Get It: in response to my out of office voicemail message directing callers to contact my co-worker for anything urgent, a woman left the following message on MY voicemail: “Co-worker, I am having this issue, blah, blah, blah. Please call me at X.” Yeah, I–not co-worker–got the message a week later when I returned.

This is a general notice informing you of the absence of [NAME] until [MM/DD]. [NAME] has chosen to exercise his right to partake in the traditions of a certain holiday which may or may not be a denominational or non-denominational.
I agree that the reasons are not relevant. But at my last company, a coworker had overly short out of office messages. Examples: “out of office today.” Or “out of office until Monday.” With no additional information about coverage, etc. Those always felt overly curt to me and made me wonder, is this person okay? Was this OOO planned or are they on the verge of a mental breakdown? (It was a very toxic culture so this wasn’t out of the question). I would be curious to hear others perspectives on this. Is too little information just as bad?