Not so. Consider: If it did happen, would you hear about it? Consider also: Why do huge, multinational companies invest so much in open license compliance programs and program offices?
I have personally helped small companies and even solo developers enforce license terms for their software. And I have seen plenty of instances of developers doing so without paid lawyer help. I have also helped small companies and solo developers sell commercial licenses for projects under copyleft, noncommercial, and other licenses meaningfully limiting permissions. Those customers have the source code. If they could simply flaunt the rules, there'd be little cause to pay for exceptions.
Why aren't these stories all over my blog? Because I can't run around blurting client confidential information. California Business and Professions Code 6068: "It is the duty of an attorney to do all of the following: ... (e)(1) To maintain inviolate the confidence, and at every peril to himself or herself to preserve the secrets, of his or her client."
There are exceptions. Sometimes at least the first part of the process happens in public, as when a company gets called out by a dev on Twitter. Those tweets are out there. And they can work when the developer's primary leverage is public relations. That tends to be true against violators that sell or hire among developers.
There are also takedown requests under the Digital Millennium Copyright Act. Sometimes, getting a company's repository, web app, or other online presence taken down for copyright infringement is all the leverage a developer needs to make a violator stop, or even kick off a settlement conversation. And DMCA notices are definitely something devs can submit themselves. I have represented clients on the receiving ends of many such requests, some of which also involved social media name-and-shame campaigns.
When settlements do get reached between private parties on license violations, they're almost always confidential, or neither side has any incentive to be loud. The activist organizations doing enforcement, like SFC, tend to see the press releases announcing settlements as big parts of the payoff for enforcement. But they are the exception, not the rule. Search around the Web for "settlement agreement form". I'd bet nearly every one you find has a built in "confidentiality" or "nondisclosure" part built in.