I grew up thinking that people would follow the spirit of open source rather than the specific letter of the law. This is obviously not true, and probably never has been.
Clearly it doesn't because companies get caught doing it with GPL software all the time.
... and the only recourse is to sue them into compliance.
Hence my thinking there is. I kept thinking EFF for some reason, but I knew that wasn't right. EFF are the ones who consistently predict which anti-privacy/anti-consumer laws will definitely get passed.
IMO, this is fundamentally a mismatch between how software is developed in practice and how copyright works.
If software was like a book, where it's finished and published once, then simply registering it with the copyright office would be all anyone needs to do: up to $10k/copy statutory damages is a stiff enough deterrent that few large companies would want to take the risk. And even if they did, it'd be easy to find a lawyer to take the case on contingency.
As a non-lawyer, that doesn't seem to match nearly as well with software as a constantly evolving work. But I'm not an expert - maybe periodically submitting versions is enough.