Don't forget Tony - on SZ you are stumbling across a tiny, tiny % of Audya owners - those that don't post here are too busy enjoying a fully fuctional instrument. Believe it or not SZ is not the center of the universe.
All the checksum test does is makes sure the sizes are correct, if the size (checksum) is wrong it is corrupt and will need reloading from the hard drive.
Its standard practice (in the UK anyway) to ask a customer to run the test if they have a suspected issue. As AJ says it is very rare for an error to occur, I have only seen it happen once in the UK.
The reason for not posting the information publically is because we do not want people poking around in the system folder without good cause..If its not broke...don't fix it.