Well technically you could only send the data to be buffered up until the sponsored content and only continue sending the stream after the content was supposed

Well technically you could only send the data to be buffered up until the sponsored content and only continue sending the stream after the content was supposed to be finished. Or a bit earlier to ensure smooth playback. If the sponsored content is blocked at least the player will not be able to continue until the time for the content or ad has passed. I can imagine people on a radio would be fine to have sound muted automatically during ads. But how many will wait for a video to continue after 30s of nothingness?