A Splatoon 2 pre-release, exhibition tournament confirmed for E3 2017

Nintendo of America have recently confirmed via Twitter that they will be hosting a Splatoon 2 pre-release tournament during E3 2017. Now this brings up the question about Nintendo hosting another World Championship tournament.
The Nintendo World Championships launched all the way back in 1990 and the last time we saw one was E3 2015 which was very exciting with games like Super Mario Maker and Super Smash Bros. on the Wii U. While the company has yet to say anything about them hosting one, it seems to be that they are leading up to the point where they will announce it with the latest news. Why would Splatoon 2 be at an E3 tournament alone for Nintendo.
It has been rumored that Nintendo has rented out a theater this year but no one from the company has stated anything about a conference or a championship tournament.
Stay tuned for more updates.