> There is no rule in copyright law that says you have to do that, and the GPL is just a license agreement at the end of the day, not a law. The best you can do

> There is no rule in copyright law that says you have to do that, and the GPL is just a license agreement at the end of the day, not a law. The best you can do is say you'll collect some fine for copyright violation or breach of contract if they don't release the source code, which was the issue of substance here too. In the US, a GPL can be both a license and a contract at the same time [1]. The distribution rights granted by a GPL to the user are conditional on the user's compliance with the GPL. Contract law allows for punitive damages. Copyright law allows for 1. permanent injunctions against the defendant's continued use and/or distribution of the copyrighted work and 2. statutory damages xor actual damages. Every GPL requires distribution of source code under the same licensing terms to users already given the object code, so the party suing to enforce the GPL can request that the court compel distribution of the source code; the court can agree or disagree. The court can also decide to give the GPL violator the choice of 1. releasing the source code or 2. no longer distributing any copies or derivatives of the GPL'd software until the violator releases the source code or 3. whatever else. The court may impose a punitive fine in any case. [1] https://sfconservancy.org/news/2022/may/16/vizio-remand-win/ https://sfconservancy.org/news/2022/may/16/vizio-remand-win/