In the past there have been instances where e.g. the Microsoft Word highlight tool has been used to... highlight the paragraph in black, which obviously visibly

In the past there have been instances where e.g. the Microsoft Word highlight tool has been used to... highlight the paragraph in black, which obviously visibly hides the text but not removing it (unless only published as an image). Drawing a box directly onto a PDF without re-rasterizing it (or explicitly removing the text from the pdf data) achieves the same effect.