Yeah, announcing you were going to delete emails unread and expecting the sender to resend when you return would NEVER fly in my office. I’d get executive complaints about that, especially if it went to a client or outside party – if a client can’t reach you, they will reach out to someone else who may not work at your organization and you lose business. I feel like this delete-it-all philosophy would only work for an entirely internal role where timelines are more relaxed, and even then, I feel it’s a bit unprofessional to foist your own catch-up work onto others, especially if they’ve been backfilling for you while you were OOO.
Just kidding, I'm not in Hawaii. How awesome would that be though, right? Instead, I'm enjoying a peaceful vacation in my living room. That being said, I'm not in the office right now, and will respond to your email after [date].

There is any number of valid reasons why you might skip on your email inbox for a while. You can be on vacation, feel sick or take a few days off to recharge.
To remind us – as if we needed reminding, as we vainly strive for ‘inbox zero’ – of just what a time drain email has become, Kay Woodward, UK-based author of What Would She Do?, has wryly channelled one of her book’s real-life heroines, Emmeline Pankhurst (and Pankhurst’s movement’s motto) in her OOO. “Deeds, not emails. That’s what the Suffragettes need. And let’s face it, I’m probably in prison anyway, so couldn’t reply even if I wanted to.”