[yowzadave]

I had a high school English teacher who became suspicious of a piece of writing I did for this reason—no automated checking was necessary! he called me in to talk with him about the work, probed my knowledge a bit, satisfied himself that it wasn't plagiarism, and gave me a compliment for writing at a high level.

False positives are not necessarily deal-breakers, as long as the teacher treats the situation carefully before taking any disciplinary action.