One was a court filing that was filed pursuant to a court order authorizing the redaction; but the material so carefully marked secret proved not to be secret at all. And then by clicking ctrl-V in another app, I pasted it with all the formatting, including the highlighting, removed. That's brilliant marketing, but when you make black text on a black background, what you see is nothing, but what you get is something else. To the best of my knowledge, Adobe Acrobat Pro redaction actually deletes the underlying text, if you mark the text for redaction and then apply the redactions. Just make sure that whatever you do, the redaction is actually complete.