This is a common mistake technical people make when discussing legal topics: they look for technical compliance. I can see why. You try and prove that code works. You think about invariants, preconditions and postconditions.

The law doesn't work that way. So much of the law comes down to holistic and subjective tests. It looks at the totality of the evidence. Those tests typically also contain questions that are also tests.

Let me give you an example: the FBI gets access to a site hosting CSAM and, in doing so, they get IP logs. Many of those logs point to US IP addresses. From this they make arrests and prosecutions.

The typical engineer defense is "you can't prove that use of my IP was me", like you could've been hacked. While that's technically true, the law doesn't work on absolute certainty. Investigators and prosecutors will do things like figure out if you were home at the time, if there's any corroborating evidence on any of your devices and so on.

So back to streaming, you look at the totality of the accused's actions. Did he get mass copies of copyrighted music? As BS as IP is (IMHO), stealing it is still a crime. Using services within their ToS isn't a defense. And the fact that you committed a crime probably means you violated the ToS anyway. Dig in there and you'll probably find stuff about not doing things that aren't illegal.