I wouldn’t be surprised if some audio watermarking is already going on right now. Universal Music Group has done this for a while on their music. In 2008 UMG was using watermarks unique to each distributor, not to each person purchasing or streaming the watermark. I’m not sure if UMG is still doing this, in the update on the first blog post linked, some said it has stopped, some say it hasn’t.

The technology to do it is already there. I’m not surprised if near-inaudible audio watermarking exists now, I’m not an expert on this field. To put an unique ID per subscriber can be done as well on a technical level I assume. I believe whether this is done depends on the streaming service or download store, because it comes at a cost of using more computing power on their servers. I don´t know whether it is allowed by the GDPR and similar laws either.

I don’t know if it is worth it either. If I look around into my social circle, most people have moved towards streaming services. Only a “stubborn” few, such as myself, still—legally or illegally—download music. Based on this, I feel like music piracy isn’t as big as it used to be.