This mistake makes the text not only hard to read, but prevents the audience from seeing the text at all. [1] If that doesn't quality as deadly sin, what would

This mistake makes the text not only hard to read, but prevents the audience from seeing the text at all. [1] If that doesn't quality as deadly sin, what would qualify? How much worse could it be? [1] So they need to reach out for different sources like archive.org and/or Google cache for the rescue.