To be invited, players had to first win a local tournament in their respective regions
Unstable introduced alternate decks with Contraptions, but had a broken incentive structure: cards like Faerie Aerie were so powerful that you were punished for putting other contraptions in your deck (since they decreased your likelihood of getting your best Contraption)
A concession causes you to leave the game, which then causes you to lose the game (Once you concede, you no longer control a Platinum Angel, so its ability cant prevent you from losing the game)
Reshiram Hidden Fates GX Full Art ACE 9
Giving your opponents no maximum hand size certainly seems to hurt the overall strategy but at the same time, triggering the Commander consistently while also helping us dig through our deck, all the same, seems to be a powerful inclusion for the list