I don't use any script that is inserting these characters, I've only noticed this by mixing parameters in $input.
I don't bother at all if this will be changed or not, that's just for making mIRC better.
The reason it doesn't show in the titlebar is because mIRC does custom drawing there for unicode support and such
Well, removing these characters isn't related to unicode or to custom drawing at all, he could have choosen to let us the ability to use these characters anyway.
If the next version of mIRC is 100% unicode ( should be ) and that titlebar's display are the same for any titlebar, that would be just nice