I think a lot of companies will allow engineers to come up with their own questions for candidates without much oversight. This can lead to the above scenario w

I think a lot of companies will allow engineers to come up with their own questions for candidates without much oversight. This can lead to the above scenario where an engineering interviewer thinks this could be a good way to check if an engineer is a key contributor or a low performer to their current role. However, it is important that interviewers are trained to ask questions like this in general rather than specific terms to avoid this appearance. I personally doubt that many companies use interviews to get IP from previous employers.