Even if it goes against the standard, I'd say it's ultimately the better solution. Imagine that when someone links you to Wikipedia, you get this:
http:
//he.wikipedia.org/wiki/%D7%90%D7%9C%D7%91%D7%A8%D7%98_%D7%90%D7%99%D7%99%D7%A0%D7%A9%D7%98%D7%99%D7%99%D7%9FInstead of this:
http:
//en.wikipedia.org/wiki/Albert_EinsteinEven if you ignore the excessive length, you can't see the article's name by reading the URL, which goes against wiki's nature.
Regardless, it would still be nice if mIRC didn't break these "Opera links".