I wanted to let folks know that Calibre Version 0.9.5 has addressed my original problem.
To the extent that it can, Calibre will prevent the user changing a book's title or author if one of the book's files is opened for editing via this message "
Could not change the on disk location of this book. Is it open in another program?"
The message was issued in these scenarios
RTF in Word
PDF in Calibre Exchange
cover.jpg in Irfanview
The message was not issued in these scenarios
TXT open in Notepad, Notepad++, Wordpad or VS Editor, open in Word is OK
EPUB open in Sigil
Calibre can only issue the message if the editor program locks the file. So if an editor doesn't cause Calibre to issue the message when you think it should, then almost certainly that will be because the editor program is not holding a lock on the file - Calibre cant fix that.
I have raised an issue on Sigil regarding EPUB files
https://code.google.com/p/sigil/issues/detail?id=1741
I don't intend doing anything about TXT files.
Thanks BR