Apparently it's considered to be against ToS and illegal if it benefits your main. Using alt accounts in GNW benefits your main since you're using the alts to help win. Since winning gets you packs from GNW that contain items to benefit your main you are using those alts in the way Oasis says is illegal. Doesn't matter if you're recharging on the alt accounts or not. It's talked about in the thread I'm linking.

http://forum.naruto.oasgames.com ... 0255&extra=page%3D2