[boredguy8]

"Spotify Free, Unlimited, and Premium accounts are for personal, non-commercial use only."

I can't imagine it's being done illegally regularly. It would be way to easy to identify by stream behavior.

[wodenokoto]

Don't CD's say the same thing?

I think it depends on local copyright laws, but I think in most places you buy a license to play music publicly and with that license you are allowed to play any music legally acquired.