Does anyone have experience with software licensing beyond selecting one for a project and applying it?

What I’m curious about is:

• Have you ever discovered someone was in violation of the license? If so:
  • How did you learn of the violation?
  • What happened next?

The reason I’m curious is that I have never, nor ever heard of, anyone other than a deep-pocketed corporate entity who has ever actually attempted to detect violations of, let alone enforce, an OSS license.

I’m highly skeptical it does, because of the resources needed to even begin litigation and how overwhelmed OSS maintainers tend to be to begin with.

I want to check my bias, though, in case this does happen more frequently and I’m just not attuned to it or how it happens.