My anecdote: During my second job in the games industry, in London, back in the late 90s — I was working for a dev-house that had just finished its first game (I joined halfway through the project).
The lead engine programmer got an offer to work in San Francisco and left the company and I took over his role as I was the only person in the company that could develop a 3D graphics engine (and had done so at my previous job).
They were desperately trying to get two games titles funded, but were having no luck, because it was in the awkward period between the PlayStation 1 and PlayStation 2 where the publishers were not committing.
Eventually they just ran out of money. I was asked to work for nothing whilst they tried to land a deal. Which I did. If I’d have left them there was no way they would’ve got a deal, because they wouldn’t have anybody with experience capable of developing the 3D engine. Selling the team is an important part of the deal.
It still failed, the business went under, and we all went our separate ways. The CEO (and founder) who had asked me to stay and work gratis went on to run a major studio. I went contracting for a while.
Then dotcom happened. My contracts dried up. I needed a job.
I called up my former boss and said “have you got any jobs?”.
His reply: “you start Monday”.
I traded away some of my cash, yes. But I gained loyalty and an ally in the industry. Obviously, most situations where someone isn’t paying you isn’t like this, just don’t fall into the “no pay, no work” dogmatic position by default.