That's pretty hard to do though: providing valid demo Spotify Premium details would be just the sort of breach of TOS that would cause spotify to come down on t

That's pretty hard to do though: providing valid demo Spotify Premium details would be just the sort of breach of TOS that would cause spotify to come down on the site like a tonne of bricks; and non-real Spotify Premium details would be almost entirely pointless (the underlying library requires valid credentials to do anything).