“If Oregon makes the program mandatory, its colleges will in effect become the only ones in the U.S. that charge students with higher earnings potential more for their education, because they will contribute more over 25 years than everyone else. Motivated students wishing to major in engineering or finance will, quite rationally, opt for private colleges or out-of-state public colleges where they won’t have to subsidize liberal arts majors. A college financing program that requires students to sign away a chunk of their future income would also be unappealing to wealthy families that have the ability to pay cash. They would probably opt for private colleges, too.”
http://www.bloomberg.com/news/2013-07-12/oregon-tuition-plan-punishes-graduates-success.html