I used to run a business doing hosting, custom software, and web design. There were several occasions on which we got screwed by customers who didn't pay, or who withheld payment until we did extra work that wasn't in the original agreement. At the time, I felt that my reputation and the reputation of the business meant that I couldn't lash out on the mailing lists of the (very small) industry were were in. When I'd had a problem with someone in the industry, though, and then later someone else had a problem, and complained about them publicly, I noticed two things: first, it didn't seem to hurt the reputation of the person complaining; second, if I had complained, my example might have saved another person from also getting burned.

I now believe that I should have made a lot of noise when someone tried to scam me in this way, and should have spent less time worrying about my reputation. I'm still not sure I should have gone as far as shutting down the (online-only) businesses which I still had passwords to, but I no longer view that as beyond the pale, as I did then.

[Edit: Although, in this case, iwwr's comment suggests it was the developer who was shady.]