The STK team added in the recent beta a feature called “live join” in online multiplayer. It means you can join a game while it is still active. As far I know, this only works for non-race games, like battle.
So far, so good.
However, there is a problem if you use it in Free For All:
Whenever you disconnect, then live join (i.e. rejoin) the server, you can:
a) Change your kart mid-game
b) Reset your score to 0
In Free For All, you can abuse this to reset your negative score. Thus you win essentially points for free. I will call this the “Rejoin Cheat”.
Note it is possible for your score to go negative by an enemy attack, too. Example: You have 0 points. If your opponent uses the switch powerup when you're right in front of a gift box, you will drive right into a banana and lose a point. All you have to do is to re-join to regain your lost point (and the hate of all other players ).
I realize this situation is quite rare, but it's still a problem that should be resolved. Thanks for your attention.