In a 2v2 game, can Tideturner be played from hidden on an opponent's turn and swapped with a teammate's unit that is alone at another battlefield to score a point?

Ruling: No, you cannot reveal Tideturner from hidden and swap with a teammate's unit. This play is completely illegal because teammates cannot have units at the same battlefield in 2v2.

Sequence:

• When attempting to play Tideturner to swap with a teammate's unit, the game checks if the outcome would be legal
• The swap would result in two teammates having units at the same battlefield
• This is an illegal game state, so the card cannot be played this way

Nuances:

• Teammates having units at the same battlefield would allow them to lock out opponents from pushing to that battlefield (since there's a rule limiting battlefields to units controlled by at most two players)
• The recall rule for units entering battlefields with 2 different controllers does not apply here, as the teammate's unit would only be entering a battlefield with 1 different controller
• Tideturner will receive errata to address this and another issue