The problem is very real, and Unicode certainly made it worse, but you can have the same issue with ascii. Capital I and l looks the same in many fonts and ad-h

The problem is very real, and Unicode certainly made it worse, but you can have the same issue with ascii. Capital I and l looks the same in many fonts and ad-hoc mitigations have been made long before computers (eg license plates). And you’d be surprised how few non-techies know subdomain hierarchy rules (facebook.com.foo.bar). Add stress, dyslexia, poor eye sight etc on top of those and you can see how this becomes a real issue. Humans simply aren’t very good at string equality. As for mitigations, in ascii only you could color code lowercase/uppercase/numbers/symbols differently I guess, enforce font that renders glyphs different enough (probably monospace), highlight the domain name, etc. But even these solutions only go so far, and doesn’t naturally translate to all of Unicode or all situations where identifiers are needed.