Me respondo a mi mismo con respuesta oficial en FAQs del sitio:
Does the "Drink of Power" card count as an
object? Can it be traded? Can it be lost?
It does not count as an object, it can not be traded,
and you can not lose it. The "Drink of Power" is in fact a "rule card" that says that the inferior (outnumbered) team can win with 2 goblets/keys. Notice: You are not allowed to proclaim the victory just with the "Drink of Power". You also need at least one key/goblet to proclaim the victory.
Básicamente una regla, no tienen por qué ser una para cada uno, no tiene sentido el anverso de objeto.