This will NEVER occur, ever, but I would be soooooo hyped if this happened at either MS's or Sony's presser. I'll use MS's as my example since that one goes first.
Phil Spencer comes out on stage. He says, "we've got a very special guest to invite to the stage... one we've never had present before. Please welcome, Sony's Chairman, Shawn Layden."
Crowd applauds widely as this came out of nowhere.
Shawn Layden: "Today, I'm here to announce an unprecedented event in console history. For the first time EVER, Xbox gamers will be able to play online... against PS4 gamers."
Crowd goes absolutely ballistic. Tears are shed, the front row is visibly shaking.
Shawn Layden: "Starting today... (pauses for more applause, camera pans to a fan collapsing into the aisle) Rocket League players will have a universal player base. Followed by DC Universe Online, Star Wars Battlefront and coming this holiday... Call of Duty."
The audience begins screaming so loudly blood begins to shoot from their collective throats.
Shawn Layden: "We'll have more announcements concerning cross-platform play during the Sony press conference. So be sure to tune in. Thanks, Phil."
Paramedics are called to attend to the survivors.