Did 'The Hunger Games' Ripoff Japan's 'Battle Royal?!'

In this article from the Chicago Sun-Times, it talks about how the extremely successful franchise of "The Hunger Games" was merely a rip-off of a 2000 Japanese novel and film,"Battle Royal." Apparently fans of the Koushun Takami cult hit novel are not pleased at all. Yet, according to author of The Hunger Games, Suzanne Collins, she had never even heard of Battle Royal until after she was finished writing the first book in the trilogy. The article continues to point out the
similar references Hunger Games has with previous films, yet, don't most
franchises often come from successful inspirations? I.e. “Pirates of the Caribbean?”
Here is a YouTube video I found about the Battle Royal/Hunger Games controversy:
http://www.youtube.com/watch?v=XxvBavHKnsE