Company Composition & Returning to Site of Origin

[miguel]

A card cannot be played for no effect. A card may be played if it has potential effect.

What exactly does this mean? May I play We Have Come to Kill just for laughs (not intending to play a character), since I'm playing it for a potential effect?

Note: If two companies end up at a non-Darkhaven site and combining those companies would violate the limitations on company composition, one of the companies that just moved must return to its site of origin. Similarly, an effect that causes such a violation is cancelled (e.g. We Have Come to Kill).

According to this example WHCtK may be played, just its effect will be cancelled? Does it mean Nature's Revenge would also be playable (and News of the Shire storable), but just the effect causing illegal company composition would get cancelled?

For example I play Nature's Revenge on Hidden Haven Ettenmoors with Troll-chief and Halbarad. Revenge's site type changing effect would be cancelled (though it would still create the automatic-attack I guess). Next turn I Call of Home the troll, would Revenge's full effect kick in now?

[Konrad Klar]

Indeed. "Is canceled" is not the same as "may not be played".

A card cannot be played for no effect. A card may be played if it has potential effect.

is one of most confusing and annoying (me) rules. Even if at declaration some action seems as not having effect, at resolution it may be different. For instance Lost in Wilderness may be played on company with only in its site path, but potentially Twilight on Morgul Night may be played in response and ultimately Lost in Wilderness will have effect on play.