except one little spell or one theory from the fic stuck in your brain. And a year later, you're sitting down to write a fic and it comes back into your head, but without that "I think I saw this in a fic once" note attached, so you have to assume it is your own idea.

I do tend to know if something isn't my idea, but not all the time. If I do remember that I didn't come up with this, I'll try to point that out in the auhtor's notes and if I do remember who the idea is originally from, I'll credit the author specifically.

The idea that made me ask this question was sort of vague but essential to the fic it was in and I didn't want to offend the author, so I figured I should ask what "due process" is in a situation like that and what most people themselves would like people did with their ideas. I did end up asking the author and she said yes, so everything is fine. :)