There is a weird glitch I found while messing around with multiplayer on this event. It doesn't seem to work in any other event.
The glitch involves you setting up a 4 player 2 vs 2 match and making the teams P1 and P4 vs P2 and P3. Once the match starts, P1 gets the top left screen, P2 gets the bottom right screen, P3 top right and P4 bottom left. It will look like this, but that's not when things get odd.
If P2 gets an item box, the item will show up in P3's screen. If P3 gets an item, the item will be in P4's screen and if P4 gets an item, the item will be in P2's screen. P1's item will show up as normal on the top left screen.
If you do 4 player on any other splitscreen event (like Dream Ski Jumping) the screen will look like this regardless of team settings. The item boxes showing each item for each player will show up on the correct screens.