> they will turn to specific performance if they think it's appropriate

Do you know of any cases with the GPL where a court has in fact done so? I'm not aware of any outcomes where code has been forcefully licensed as a penalty. Absent strange outside circumstances (like a signed contract) I'd instinctively (but without legal training) think that that a court would treat the violator as "acting without a license" rather than "had specifically agreed to the terms of a contract and then broken it".