[Geoff Bacon]

There could be hundreds of "double occurences" - would anyone want to be asked a question about each one?
By automatically adding the entries, you have the option of sorting them out at your leisure.

Always make a backup before making major changes to the database e.g. deleting lots of songs. This takes hardly any time and provides a fallback should it not go as envisaged (like here)

Cheers
Geoff