If instead you ask your co-workers to cc or bcc on replies then you will know which have been dealt with. (I think for internal mails it’s more reasonable to ask that if the original person contacts someone else, they cc you so you know who is dealing – and in smaller organisations where people know you personally you could also send a mail round the day before you leave to say you’re going to be out and to ask that any enquiries are directed to [name]in your absence, to try to avoid them coming into your inbox in the first place.
I might sound nitpicky but the language is important. “Might” or “may be” or “slower than usual” are vague and don’t offer the sender all that much information about when you’re really going to respond to them. Worse, they do a horrible job of protecting the time of the email receiver who, as the responder notes, is not in the office! Such a responder implies that, not only will the vacationer reply to the email, but they may not even miss a beat. They may be slow to respond, but they also might not.

Whatever style you may adopt, it’s still useful to know that some of the general rules apply to all instances: Stay consistent with the preferred communication style, particularly if you go for more creative options Double check for grammar and typos, as your template will be sent to many addresses Do not overdo it in terms of using unconventional style, particularly if you are not sure that it will fall on right ears with some of your customers Wrap-up
Sure, Kopelman is truthful about the fact that he's on vacation, but he also lets the recipient know that he or she would be interrupting important family time if the first option is chosen. It states a point simply and uses humor to avoid making it sound like he wants the reader to feel guilty.