Board Thread:General Discussion/@comment-4962906-20151110063326/@comment-5925413-20151110064716

Farerb wrote: Joshleung wrote: Arthur and Zelena conspires. Arthur and Zelena don't remember anything.

Unless we don't see them drinking a memory potion before they go back to Storybrooke, I wouldn't say we know that for sure. We haven't seen them that very much in town, and as tricky as they are, they perfectly can lie.

So for now, the theory remains valid to me.