So much of genealogical research is based on instinct and guesswork, but so many people completely fail to cite their sources. I don't know if it's just ignorance, or if it's an attempt to obfiscate, in which case the whole thing is made personal: "Trust me, I wouldn't lie to you."
But it's not about 'trust', it's about relative value.
I mean, if I want to say that I had a dream in which my ancestor convinced me that her middle name was 'Shazam', fine, but if I want to tell other people that her middle name is 'Shazam' then I'd better say that my source was a dream.
What I find over and over again is that people don't then cite either my source or me and then it begins to look like 'fact'. What's that old saying? If you say something three times it's true? What does publishing it online make it? That you've said it 1,000 times?
I discovered today that I'd made a mistake in my database - typed "David J. McRae" when all my sources said "Daniel J. McRae" (and it was the name of his uncle), so I fixed it. And then noticed that three other database on rootsweb had the same 'spelling' error. Obviously they had used me as their source and not even looked at my sources. They did not note a source at all.
That's how mistakes get passed on...