I've read the FAQ (1.44) regarding "either X or Y" but unclear regarding particular Treachery. The "Cornered" treachery in Trouble in Tharbad says, "When Revealed: The first player either removes 1 time counter from the current quest or each enemy gets -20 engagement cost and +1 attack until the end of the round."
There are no enemies in play. So can I choose the latter? It seems I'm performing the effect "in full" as 1.44 says -- there just happens to be 0 enemies... but not sure.