Why ci url does not support Chinese

[eluser]chaochao[/eluser]
this is right?

[eluser]yinzhili[/eluser]
Look at this:
http://tinyurl.com/kkwxcq

[eluser]Shiro[/eluser]
I am not agree with "You cannot use chinese characters in your URLs"
because currently ICANN they just want to launch a chinese or other character in domain name. such as .中国 instant of .cn

I do some testing today, I use php urlencode function to encode the string
http://localhost/sandbox/% E5 % AE % 9E % E9 % AA % 8C % E5 % AE % A4 (join it plz, CI Forum help me decode....)

the thing if u copy and paste the string there and paste to browser, it will automatic convert to Chinese character.
It will display:
http://localhost/sandbox/实验室

and I print_r($_GET)
it display
Array( [实验室] )


And for the issue:
exit(‘Disallowed Key Characters.’);

I would like to ask, is there any harm not filter the key?