Board Thread:Spoilers!/@comment-75.120.62.171-20130126130624/@comment-5679696-20130126202428

I dunno :S The dagger has magic. Storybrooke has magic. All the world surrounding Storybrooke is The Land Without Magic. Taking this in account, if someone uses the Dark One's Dagger to summon the dark one from outside Storybrooke, the Dark One should not be forced to do anything, the other way round, if the Dark One is outside Storybrooke, in a place with no magic, and someone from inside summons him, the magic of the dagger will not "leave" Storybrooke, and so the  Dark One will not be forced to return.

Anyway, Mr. Gold needs to return, because of Belle. and when he crosses the line back to Storybrooke, Cora will have power over him because of the dagger.