It's not an error at all, Simon! Because different setups in the past lead exactly to the scenario that you depicted. Examples: projects that requested signed copyright transfer for each patch (even GNU projects required this). But also what is more insidious is that very complex projects, while sometimes BSD or similarly licensed, were made completely proprietary (and not under the MongoDB / Redis circumstances, but just to turn proprietary for other reasons) but they were so complex internally that basically you can't do anything with the code, without paying like... 50 engineers to study it for six months. So it is an actual danger, but not in the case of BSD + projects that have an acceptable barrier to entry to be understood, fixed, modified, ...