My question title is a bit vague but this is a discussion question so I feel it sums up the idea of my question the best.

I so far am active on this site and on Sci-fi/Fantasy stack exchange. I prefer the dynamic on this site and the openness of the community which I hope isn't just because it's in Beta. I'd like to address an issue that I keep running into on Sci-fi/ Fantasy because I feel it's an issue that could affect this site as well. There is a trend of sorts of marking questions as possible duplicates when they are similar to other posted questions or answers that match similar content. Now I know that what I just wrote sounds like a basic statement of how to mark a duplicate question but there is more that needs to be taken into account. One or two high reputation users will mark as duplicate and it seems like users simply agree rather than think on it or listen to reasons why it's not a duplicate. Also this starts to become an issue when a topic starts to become saturated to a point that almost any question borders on possibly being a duplicate to a previous question or answer. (How there is possibly any Harry Potter questions left that can be asked I don't know) 

I have not come across this problem on this site yet but in the future it seems to be a possibility. I see it as a possibility simply because both sites are trivia sites in my opinion and therefore can be open to opinions as answers which can then be accepted. Even non-accepted answers can cause duplication though. Now it is always up to the asker to insure they are not duplicating but when the questions on the subject become too numerous it is not only hard to look through for duplication but sometimes even addressing a question similar causes duplication to be flagged. 

So I want to open this for discussion because I think setting a standard way of handling possible duplicates especially before the site graduates can help a lot.