If you were foolish enough to send your code to someone else's LLM service, they know exactly where you used their output.

If they wanted to, they could take that output and put you out of business because the output is not your IP, it can be used by anybody.

I doubt it will be enforced at scale. But, if someone with power has a beef with you, it can use an agent to search dirt about you and after sue you for whatever reason like copyright violation.

It will be enforced by $BIGCORP suing $OPEN_SOURCE_MAINTAINER for more money than he's got, if the intent is to stop use of the code. Or by $BIGCORP suing users of the open source project, if the goal is to either make money or to stop the use of the project.

Those who lived through the SCO saga should be able to visualize how this could go.

It will be enforced capriciously by people with more money than you and a court system that already prefers those with access and wealth.