Well how would they filter out emojis? My assumption is, that they're doing it by exluding Unicode code points for all emojis.

> My assumption is, that they're doing it by exluding Unicode code points for all emojis.

Yes? The code points of emojis are excluded by HN.

Try it yourself with characters of different types! Ones that are neither ASCII (including builtin html entities, sure) nor emoji.