This is a special feature of Nash guitars that I was not aware of. From their FAQ web page:
Can I play "Freebird" or "Stairway to Heaven" on my Nashguitar?
My guitars come with a special chip that senses these and several other songs. If played, the guitar will melt and mutate into an 8 track player (thus voiding the warranty). For a complete list of non-playable songs
GO HERE.
They should give these chips to GC to install in their displays.
What other chip(s) would you design?