It also states further down that violations of the guidelines may result in immediate termination or suspension of one’s Spotify account. That said, the language used isn’t the clearest at describing it, considering it follows the section describing the posting of user content.

That said, an explicit banning of ad blockers is an expected move. The service very recently reported its first profitable quarter in 13 years after all. If anything, it encourages the service to keep growing, and one of the clearest ways to doing that is to allow ads to run their course. The new Terms of Service is stated to be effective as of 7 February, which means that the music streaming service can and will terminate account without prior warning. So, If you’re invested in your Spotify account for whatever reason, now’s probably a good time to remove or disable ad blockers functions that specifically target the service. (Source: Spotify via The Verge)

Spotify Will Begin Banning Accounts Using Ad Blockers - 20