If a player taps 8 runes then decides 6 is enough, but their opponent calls a judge saying they must float 8 energy, can this be rewound at high OPL?

Ruling: The judge would most likely allow a rewind to remove the extra energy from the rune pool, as no new information was gained and the game state hasn't changed.

Nuances:

• This is a case-by-case judgment call that depends on the specific circumstances
• If the player exhausts 8 runes and immediately says "oh nope" and readies 2, that's a valid rollback
• If the player exhausts 8 runes, plays a 6 energy spell, and then says "oh nope", that's a very different case and would not be allowed
• The key consideration is whether new information was gained because of the action