Board Thread:Spoilers!/@comment-26159109-20160301190120/@comment-24674051-20160331163251

My understanding is that they are done filming in Steveston, not necessarily done with filming entirely. The EF scenes (and any other set type scenes) are done in studio (and generally behind closed doors). So anything that happens on set is not spoiled unless the writers/Directores/execs want it spoiled.

That's how they pulled the Elsa surprise at the End of Season 3, and why Emma becoming the DO was spoiled so easily in Season 4 (use and lack of use of studio/closed filming). My guess (and hope) is that the key pieces of the Finale are done on a closed set to prevent spoilage.