Most students receive financial support from their parents and have ample disposable income for products like GitHub [0,1,2]. Recent grads who want to keep learning about technology are more in need of discounts.
I'm not discrediting GitHub's campaign — I'm happy that the company is reaching out to students. It's just that the trend toward offering students discounts is somewhat misguided and shortsighted.
[0] http://news.byu.edu/archive12-apr-payingforcollege.aspx [1] http://www.nytimes.com/2013/01/15/education/parents-financia... [2] http://www.usatodayeducate.com/staging/index.php/choice/who-...