[jcwilde]

Am I to understand from your explanation that they asked you to solve a real business problem with real business data as an unpaid "coding test"?

If so, I'd say they were clearly in the (legal) wrong even before asking for the refined version.

[bweitzman]

I had an interview at a company once which was basically pair programming with a few different engineers for a full day on real code written for real clients. The best part was the NDA they asked me to sign 6 months later.