Language is flexible but not THAT flexible

My mum teaches sociology (among other things) to adults. She has been told she can no longer let spelling and grammar influence grades. Which is basically saying, "write whatever the hell you like."

Now, missing the odd comma or misusing a semicolon is one thing, and English is a living language. Its style and vocabulary have evolved over more than a thousand years and if you go back to Shakespeare's time it verges on the incomprehensible to modern ears. Unfortunately, the errors that students make are not merely misplaced apostrophes or splitting infinitives. I don't have that many examples saved for posterity, but here are two of the lesser and funnier variety :

"The purpose of this essay is to establish whether or not criminals should in fact be incinerated, whether incineration works, and indeed, whether criminals who have previously been incinerated should be re-incinerated upon their re-offence."

""Nowadays people are eating unspoiled and preserved food, pastoralised milk, sterilised medical instruments and well developed antibiotics and vaccines."   [Yum!  That stethoscope went well with the blessed milk]."

There are many other far worse examples where it's not even clear what the student was trying to mean.

Yes, English changes, but that's not supposed to mean you can get away with linguistic murder. These people are supposed to be going to university and in many cases (horrifyingly) into nursing and social work. If you can't string a sentence together what hope have you for understanding and communicating with those who are most venerable, I mean, vulnerable ? And what's the point in being a teacher if you can't give people poor marks when they get things wrong ?