The user can already prove they own the game. Ubisoft accepted the proof. The problem is they've chosen to configure their servers to reject sending the game cl

The user can already prove they own the game. Ubisoft accepted the proof. The problem is they've chosen to configure their servers to reject sending the game client messages consistent with this proof. They could, if they wanted, configure their servers to send network messages approving his login. But they choose not to. If a company opts-in to using your NFT as the authority, they can at any time opt-out(just like Ubisoft did here) so it provides no extra guarantee. And companies that don't accept your NFT as proof will ignore it when it's presented as evidence.