Style guides come up, though, because students know that they are out there, but they generally don't have a very firm grasp over what they are or how they work. I do require some familiarity with MLA style because I require its formatting for paper headings and things like margins and spacing. I make formatting a (small) part of my grading criteria, and there are inevitably several students who lose a few points for not double spacing their lines or not putting a title on their papers.
Students don't like this. They think that it's nit-picking and frustrating. It's not "real" writing; it's just annoying. I know what they meant, they insist, so I shouldn't take the points off.
To help demonstrate why paying attention to these details is more than just a place for me to penalize them, I remembered an activity the SLU Writing Center had used when I worked there. I adapted this activity for my developmental writing students, and I was happy with the results.
I divide my students into two groups and then tell them that we're going to have a contest. They need to imagine that they've just entered a busy restaurant.