I could be wrong, but I thought i read somewhere along time ago, how it worked with Spotify was the play data was still tracked by the app, and when ever you connect to the internet the play data gets sent.
So in theory if you download a bunch of songs, play them and never connect to the internet with the machine again, the artist wouldn't get paid.
Pretty safe to say that most likely very rarely will ever happen.
You could prob dig through the terms and conditions and find out the answer, it would likely mention if the play data was being tracked and sent.