I'm a new user so can't speak to longer term history, but there was about a months notice if not longer. It was a stickie post in the forums listing the songs that GuitarTricks was due to lose the license for.

There was quite a lot of heat in that thread, but I'm not sure what people think that they could have done differently. I'd anticipate that they're negotiating the rights to songs leading up to contractual anniversaries. Sometimes negotiations fall over late in the piece and they had to work with the timeframes remaining.

Subscribers were advised of the impending lessosn being lost in advance, also that new music/lessons were being prepared.

Seemed fair.