This is why we have to distribute stuff through PDFs or HTML.
I had one of the Word documents up on my screen when my son starting toying with the computer mouse. Somehow, inadvertently, he managed to pull down the “View” menu at the top of the screen and select the “Mark up” option. If you are in a Word document where “Track changes” has been turned on, hitting “Mark up” will reveal all the deletions and insertions ever made in the document, complete with times, dates and (sometimes) the initials of the editors. When my son did it, all the deleted passages in a document with the innocuous name “Administrator’s Weekly Economic Report” suddenly appeared in blue and purple.