[hannele]

I'm curious, why is it allowed to register domain names with mixed character sets? I am behind allowing Unicode characters in domain names for the obvious reasons, but are there compelling use cases for allowing them to be mixed?

[klodolph]

Technically, Unicode is only one character set. If you want to disallow mixing, you have to disallow it on some other basis, like script. There are many edge cases to consider, though, and many legitimate reasons to mix scripts.