All the candidates I gave serious consideration to write lots of code (as did my staff who also interviewed them). But I can't interview everyone whose resume I receive: I can only pick the best resumes. When a candidate failed the interview process, I tried to figure out the error I made (if any) in order select better resumes in the future.

And I agree that schools are different. I occasionally considered candidates from schools that people snicker about, like San Jose State. But they had better have aced everything and really stand out from the pack to overcome that handicap. Sometimes, great people have life circumstances that corral them into lame schools. On the other hand, I'd give pretty serious consideration to a candidate from Harvey Mudd or CalTech with a 3.1. (But even at those great schools, the < 3.0 rule seemed to apply: candidates with a really low GPA couldn't pass the technical parts of interviewing. You'd be surprised how many CS graduates from top schools can't implement the C library strrev() function or return a pointer to the nth element of a linked list.)