Also, someone commented that tutors are not aware which applicants are open. However, the college admissions office must know so are we saying there is a chinese wall within the college?
There is a central university admissions department and then the colleges. It is indeed true that the former doesn't let the latter know which candidates are open (or second interviewfor science subjects). They also do things like withhold admissions test scores until after interview to try to make them less biased - there is a well established 'Chinese wall', as you put it.