Also when writing (as opposed to talking) you can actually use quotes (as demonstrated by the quotes around "quote unquote"). However in the case of "benign" the quotes are implying, correctly, that it's not benign at all. My preferred method when talking is to use hand signals for quotes, question marks and on occasion, exclamation points.

Since HN has a large number of English language learners in the reader-base I figure this spelling is less likely to induce confusion.

If we're splitting hares, I feel like it's more likely to confuse people whose first language isn't English. Why introduce an incorrect parsing that sounds similar? That's more likely to lead learners astray than help them understand the idiom.

I wouldn't recommend trying to split hares.

Why not? If you've got a hare to butcher, you'd likely want to split it. You could leave the carcass whole and roast it, but that's only one of the many ways to use the animal.

If you want to argue over details that make little difference though, I'd recommend using the term "splitting hairs" instead.

I was jesting but a serious reason why 'quote unquote' may be confusing is the fact that this kind of immediate negation is not considered correct grammar in any other context I know of.

'kind unkind'

'known unknown' (unless your Donald Rumsfeld)

'seen unseen'

etc.

Not my Donald Rumsfeld.

I feel like writing quote-on-quote takes away the ability of non-native speakers to search for and learn the basis of the idiom. I really don't see how it would be more understandable than just typing "quote".

How would it be less likely to induce confusion? What is it even supposed to mean in that form? I had no idea what you were talking about until someone explained your error.