Is attention to grammar and mechanics a big factor in getting a good mark?
There are some of us who actually grade and have sort of grammar and mechanics of it all as you say sort of as part of the grade, or we'll take it off...take off marks if it's particularly poor. A lot of people don't; however, if a paper is really poorly written with lots of errors, you have to, even subconsciously, formulate an opinion about that piece of work or that person. And, you're either going to think the person is dumb, or you're going to think they're lazy, or that they just don't care. I'm always amazed that, even today where everyone uses a word processing package, that there [are] still lots of spelling mistakes and whatnot. That's just sort of sheer laziness: that no one's read anything beyond typing it. So, when you see that kind of poor effort into an essay you're either going to directly give it a poor grade, or you're going to subconsciously just think, "This isn't very good."