When I used to take my Associated Board Piano Grades, you had the pieces book for each grade (containing a choice for each List A, B, and C). There was also a list of alternative pieces which could be substituted. In my day, this meant getting hold of the music to see what the alternatives were like, and then if suitable buying an often expensive volume, just to get the one piece needed - or rely on the library, and hope no one requested it just before your exam!
Today it’s so much easier, as not only is there a CD with each grade, which includes all the pieces - those in the book, and the alternatives - and there’s also the internet where you can listen to, watch performances of all the pieces, and download the music.
This has thrown up an interesting scenario. Wherever possible, of course, the Associated Board will recommend its own editions of music, not simply because they’re the best (and I don’t subscribe to this, when you look at how some Bach Preludes & Fugues and Beethoven Sonatas have recently been quite badly edited) - but more importantly because they want your money - even more of it!
It is now quite legitimate to use downloads, as long as these are accurate editions, and are out of copyright. The problem sometimes occurs when these downloads are occasionally nothing more than photocopies of another edition - then sold free. On paper this would appear just like a photocopy, and could be a problem in the exam.
To this end, I have edited two pieces which are currently alternative pieces at Grade 8 (one for List A, and the other for List C) - I have added fingering and tidied up some of the notation. It is totally permissible to use these in an exam (they will expire in the March 2013 session).
Just out of interest, Scarlatti and I share the same birthday!