After viewing this user name (which contains a lot of Unicode) I had the idea to test if usernames allow ZALGO. To my dismay they do.
Is this wanted? Together with ShadowWizard we did a quick test. ZALGO has the ability to "break" comments.
Shouldn't that be avoided before someone start abusing it?
EDIT: little clarification: I asked around and it seems that some time ago Zalgo didn't work in usernames. So it seems that some "recent" change broke that rule. While it is true that missuses could be handled manually, it could be worth to check why the behaviour changed suddenly (assuming my sources where right).