Something mildly similar is how spam emails made it through our filters. In the email it'd advertise dick pills but when copying the email to notepad it looked like gibberish. I made the suggestion to highlight the email text and change the font-color and size to something uniform. Turns out they would insert 3 random characters in between each letter, and those 3 characters would be font size 1 and white while the letters of the actual message were 12 and Black.