As I mention there is absolutely Zero need for a PSN user to create an XB-Live account. There would be a unique encrypted user ID hash. No account information would be shared. No personal information would be shared.
The sole purpose of that encrypted user ID hash would be to determine what the user's gamestate is (DLC unlocked, etc.)
So, for example.
- PSN user has Minecraft and wants to do cross platform play.
- PSN passes a unique encrypted user ID hash to XB-Live to represent that player.
- User purchase DLC on PSN. PSN passes on to XB-Live that this user ID now owns said DLC.
- User uses PSN to log into the game despite all data residing on XB-Live servers.
- This is how FFXIV works BTW. Except obviously not XB-Live servers, but Square-Enix servers.
- At no point does the user have to create an XB-Live account. At no point does PSN pass on user account information to XB-Live.
- For player convenience however, a user might be asked to input a name that other players can see them as. Or, PSN could provide the person's PSN name associated with the user ID hash.
There's a variety of permutations of this that accomplish the same goals without the sharing of user information or the user having to create another account.
It happens all the time on Steam. There are many games which operate on 3rd party servers but which do NOT require a user to create a 3rd party account. Steam passes on an encrypted user ID hash for the 3rd party server in order for that server to properly track what that user owns. User only ever logs into Steam and doesn't ever explicitly log onto the 3rd party server or create an account on the 3rd party server.
Regards,
SB