That's like saying it's wrong to flank some plain text with underscores or asterisks if the UI is not parsing that into rich text; actually the parsing isn't necessary for successful conveyance of emphasis (and the convention predates such parsing). By analogy, parsing of the @username syntax into a ping isn't necessary for successful conveyance that the word is a username (although I'm not sure the convention predates parsing in this case).

Just as seeing underscores/asterisks is understood as "the author is emphasizing despite lack of formatting," seeing a leading at sign is understood as "the author is saying 'this word is a username' despite lack of ping."

That was always understood. I just didn't want confusion with the word dang.

I seem to remember the early days of twitter @username also didn't notify the user or even highlight, same as hashtags. Here is an example: https://twirpz.files.wordpress.com/2015/06/2008_07_26-twitte...

Same with Outlook, now when you @-someone it highlights them and even adds their address "To".

Just because HN doesn't currently support this syntax, doesn't mean we must not use it. As with the other examples, if enough people do it, I wouldn't be surprised if support is added later.

Thankfully, my username is pretty unique (like yours), and I can easily search for references to me, but if my name was a common word it would be really frustrating trying to weed out references to me, compared to where people are actually referencing me.