What color do you check someone's paper by??

From Ellen's blog

In your school, Does your teacher use red color when (s) he check something like tests or another assignments??
According to the Ellen, there is the article that insists teacher shouldn’t use red because red represents not only love but also debilitating and causes stress.
Moreover, in the article (not written by Ellen) one teacher useing purple said “My generation was brought up on right or wrong with no in between, and red was always in your face. It’s uncomfortable to me. Purple is just a little bit more gentle. Part of my job is to be attuned to what kids respond to, and red is not one of those colors.” This remark is interesting, at least, for me, because Purple represents frustration in Japan (I don’t know how this color is thought in another countries). However, it said that the frustrated Purple pens’ sales are rising.

For me, the color doesn’t become any trouble because since I enter elementary school, teachers have used red pen. So I had never cared about the color. I think , unless the color is black, it’s all O.K. that whichever colors the teacher use. How about in your country?? And how do you think if the teachers use only red color in that case?