Questioners tag questions based upon the context in which they are asking. They may for instance ask a question about what module could display information in a specific using the module tag. The answers might very well include the Views module. Is it appropriate to add views to the question?
Does it matter if the tag is added before the question receives the answer? (I believe it should not be added until after an answer includes the Tag, but I would like to hear other opinions on that as well.)
I believe it makes sense to add a views (or any other module that is part of an answer) so that future visitors can reference the question which, in the end, involves using a specific tag, even though the original questioner was not aware of it when they tagged the question.