I'm inclined to think so after looking at the answers to this question:
How could Leia sense a specific death among so many?
Read, hover, read, hover, read, hover...
Do we really need spoiler protection on answers to questions? If the question title is sufficiently vague, and the question itself uses spoiler tags, and nonetheless someone is clicking on the question to read it, can we safely assume at that point that they want to see the answers and we don't need to protect them from spoilers?
Off the top of my head, I can think of a few reasons we want spoiler markup in answers:
Review queues. Because you can't exclude tags from the queues, I got more than a few things spoiled for The Force Awakens just because I spend a lot of time there. This is perhaps a weaker reason, because many of the queues focus on questions, and the ones that focus on answers overwhelmingly focus on new or bad answers (which are less likely to use spoiler markup in the first place), but still; if the rationale for hiding spoilers is courtesy (and it is), then even small courtesies are positive things.
Mods. So, I'm not a mod (obviously). I don't know how modding really works. But I'm fairly confident that mods still have to moderate on things they have not seen. Our intrepid mod team still has to keep an eye on unpleasantness in The Force Awakens questions (and answers), even if they have not seen the film. Spoiler markup in answers is a (admittedly small, in he grand scheme) courtesy we can offer to them.
Ongoing series/franchises. This is my biggest argument. I realize this question is motivated by the glut of The Force Awakens questions, so this reason may not apply in the specific case, but it does in general. We have a lot of questions asking about ongoing franchises or series, and people don't always wait until they're fully caught up to ask their questions.
This is also a problem with older works, mind; I know of at least two users (you know who you are), who asked questions about The Lord of the Rings books (a series that was completed sixty years ago) while in the middle of reading them.
As an example, consider How did John Winchester escape from hell? (top-voted answer by me), a Supernatural question. Although I couldn't be sure, the question strongly suggested to me that the asker hadn't watched past season 6, while the show is currently in its 11th season. Accordingly, I put some things in spoiler markup, because the OP may not have gotten far enough in the show to know those things. Should I not have done that, and changed the OP's viewing experience later on? I don't feel like I have that right.
Having said that, I do appreciate that some people don't care about spoilers (whether they've already consumed the media being spoiled, or if they just don't care at all), and for them reading something like the linked question (and its answers) can be frustrating. I get that. But I think there are better solutions than blanket-banning spoiler markup in answers:
A global "disable spoilers" button. This would be a network-wide change, have to be requested on Meta.SE, and may not be accepted (I haven't done the research to see if it's been done already), but something like that TVTropes has: a button on each page saying "I don't care about spoilers; make everything visible to me" would handily resolve this problem. People who care about spoilers have them, people who don't do not.
Better use of spoiler markup. One thing I try to do (not always successfully) is try to make reading the spoiler markup an optional experience. If you're familiar with the work, you should be able to glean enough detail from the surrounding (unspoilerified) context to have an idea what the spoilered content is going to say. This admittedly doesn't work for people who haven't seen a work and don't care about spoilers anyway, but I'm open to suggestions on that front.
Contrariwise, we could try to condense use of spoilers into a few larger blocks, rather than having spoilerified sentence fragments peppered throughout. This has its own problems, notably that for some answers necessarily have so many spoilers that the answer becomes less useful for being almost-entirely spoilered. But it would reduce the amount of mouse movements, which is something.
