I would bet differently, having checked the evidence.

http://www.businessweek.com/magazine/content/03_27/b3840045_...

http://www.educause.edu/ir/library/pdf/ffp0621.pdf

http://www.educause.edu/ir/library/pdf/ff0615S.pdf

http://www.tcf.org/Publications/Education/carnrose.pdf

http://www.tcf.org/Publications/Education/kahlenberg-affacti...

http://harvardmagazine.com/2005/05/a-thumb-on-the-scale.html

http://www.theatlantic.com/doc/200511/financial-aid-leveragi...

http://www.thecrimson.com/article.aspx?ref=510012

http://www.equaleducation.org/commentary.asp?opedid=1240

http://www.jkcf.org/assets/files/0000/0084/Achievement_Trap....

http://www.reason.com/news/show/123910.html

The most disadvantageous position to be in, in United States college admission, is to have little money. Low-ability, high-income college applicants fare much better in the application process (they end up with more and better choices of colleges) than high-ability, low-income students.

P.S. The submitted article, contrary to the HN submission title, refers only to grade averages at college, but I think there is also considerable evidence, for which I have fewer convenient citations,

http://www.amazon.com/Wad-Ja-Get-Grading-Game-American-Educa...

that higher-income, lower-ability high school students tend to enjoy better grades than their lower-income, higher-ability classmates. Teachers respond to signs of wealth.