Till about 2006, the lunch "interviewer" was able to put in feedback, but was specifically told that they were not supposed to do it.

Except for some smart alecks who would put in "Candidate held fork in left hand, was neat eater" I never saw anything beyond "n/a" or similar non-feedback. Most often I would see a savvy recruiter pair up the lunch with the referrer so they could catch up with their friend and it would act as the 'sell' part of the interview slate.