If Spotify wants to deliver free music bundled with advertisements, it's on them to implement that bundling correctly. If their implementation is two endpoints, one that returns music and another that returns ads, and they just politely suggest that everyone who uses the first endpoint also uses the second, I am in no way obligated to follow their suggestion.

Spotify is free to implement a less laughable implementation of ad bundling, and they're free to block my free account if they don't like my behavior, but I will always oppose any claim that I am obligated to make a request to endpoint B (and execute the code it returns!!!) if I make a request to endpoint A.

For clarity, the "I" in the above paragraphs is hypothetical. I don't use Spotify, but I do pay for Apple Music (not because I feel like I owe them, but because I like the service and think it is worth the price).