In the specific case of using the GPL as a part of your licence, a court could potentially rule that the additional restrictions are removable under the 'Additi

In the specific case of using the GPL as a part of your licence, a court could potentially rule that the additional restrictions are removable under the 'Additional Terms' clause. The licensor could have created a derivative licence with that clause removed (as well as renaming the licence and removing the preamble, as required by the FSF when creating derivative licences based on the GPL). If they did not, the licensee might have grounds to believe that additional terms are removable. In the case cited in the earlier link, the court disagreed, but another court might conceivably have a different opinion.