Actually it doesn't make much sense. How would your specific mIRC know of all the urls everyone ever found? By connecting to the website holding the file and checking everytime? Or by downloading the file every few hrs? Then of course - how are you goinf to stop people from adding fakes to the bad-url list, seeing as how no one is ever gonna have enough time to check all those urls.
The best solution is to use one's brain. Don't click on any urls posted by people you don't know. If such ways of spreading a virus are to be stopped, the answer is not to make life hard on those who know what they are doing, but to educate the ones who don't know.