if i were to institute something like this, the driver would be fairly (and well) compensated to do this task. Any tips would be handed over at the end, so there's no consideration of compensation involved. Obviously tipping is a data point, but it wouldn't influence the drivers report beyond that checkbox.
Now we're adding wage-theft on top of both assessing candidates on their disposable wealth, and accepting and keeping payment from them? The ethics get pretty muddy the further down this path we walk.
i find most things murky if you really try to walk for a while.
I always find it interesting how i'm perceived. I didn't intend wage-theft as part of the idea. Also it is possible that there's people who are qualified to do this work (passenger/commercial endorsements on their driver's license), good character actors, and generally ethical.
I took it all as a thought exercise, anyhow. Having been on the hiring side of the table, i'm not the "team fit" or "social" interviewer. Technical and creative questions. I let people in their fields deal with how their interviews go.
So all told i wouldn't be in the position to hire someone to filter potential hires.
I think where this might get dodgy is with the possibility that some of the candidates might have tipped this driver, which puts us in the position of asking for an opinion about several candidates from someone who might have been compensated by some of them.