I tell my students to read through what they're about to hand in before they hand it in. Few do. Even some PhD students will submit a thesis that they haven't read through. I can understand it for short emails, or for blog posts written on laptops at airports, but for formal writing it's wise to make sure that what you've written makes sense.
Still, if the Essex County Standard is the standard to which the county of Essex aspires, I can understand why so many students may have better things to do with their time than re-read what they've just written.