Disco Nunu held me hostage in a ranked game yet again!

http://s1381.photobucket.com/user/wonderpeel/media/disco%20nunu.jpg_zpsy8tf0kkx.png.html

Why is this not bannable? Why should 4 people be held hostage while this guy can get off without penalty and I have to lose lp? Disco nunu is becoming quite popular nowadays, and nothing can be done about it because there's no reporting in champion select. I really debated violating name and shame because this guy deserves to get banned along with many players like him. @Riot @Lyte