Why would interviewees believe you? I have heard such claims before and assumed they were false and treated lunch as just continuing the interview while doing something we all had to do anyway. If the interviewee raised numerous red flags, the interviewer would absolutely be sworn to silence? Even informally?
I wouldn't blame them for not. However our integraty means we will anyway. And that the lunch people don't have a voice is carefullp monitored by hr just in case something goes to court.
I don’t work in tech.