By fairly large margins we've agreed we are a spoiler zone, that its expected and normal. As we've had a little edit thrash today I think we need to better define what that means.
If the OP wishes to place a spoiler warning then I have no issues with that. As spoilers are an issue in the various forms of internet discussion we should go with the original poster discretion as to whether they use tags or explicitly state it at the beginning of the question. The more explicit the warning the better the chance that somebody who care about spoilers will understand what is going on.