I'm struggling with this part of the Creative Commons Attribution 4.0 International (CC BY 4.0) license:
No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
A storyteller (Mr. S) is recording his own narratives / stories. He adds sound effects (like footsteps, wind, rain) to the recorded audio files. These sound effects are licensed under the CC BY license. The original sound effects are modified by Mr. S to fit to his recording.
Mr. S has a website where registered, paying users can listen online to his stories. So he is selling the access to the audio stream of his stories - he gives all the required attribution of the CC BY license to the creators of the sound effects.
But, his own legal terms do not grant any rights to the listeners (the paying users) to share or sell his audio files, nor adopt or remix them or use in any other way exept to listen to them.
Is that allowed by the CC BY license?
I think it is, but what does the quoted part of the license mean?
All I found in the FAQ's about that part is about sharing a CC licensed work. But in Mr. S's case he is not sharing, but selling his own work (which uses modified parts of CC BY licensed work).