Not programming, but in the same vein, A Trek Bicycle store manager asked me in an interview if I would be willing to work a trial shift the next day building bicycles. Unpaid, of course. Just to see if I was a good fit.

Of course, since I was used to building 50 a day, I would have gotten all of them done in a single shift whereas they were needing to call in stores from surrounding areas to come help in a few days.

I laughed and said if they needed help tomorrow I would be happy to work for my usual fee of $20/bike.

Oddly, I did not get the job

Notice the "cook" in username. Unpaid labor is a common practice in the restaurant industry. They call it a "stag". It's supposed to be an unpaid working interview, but restaurants will schedule stages with people even when they aren't hiring.