I don't think we've heard anything from SE regarding the rules of the tournament yet, so I'm going to speculate.

1) Random rule in effect. Nobody gets to choose their deck, to weed out everyone who tried to farm cards against overpowered NPCs. This rule does not affect NPCs.

2) Chaos rule in effect. Why should you get to choose what card to play? It's only fair to let SE do so for you. This rule does not affect NPCs.

3) While Random is in effect, you won't be allowed to break rarity rules in your 'randomly' chosen deck. This rule does not affect NPCs.

4) Win/Lose is a hard statistic to track. Instead of ranking players, let's decide on first three finishers with a /random role.