I'm no longer sure of my statement. There is a file list that is maintained (Database.mpl), and the file paths are checked. Certainly the files need to be read on sync (for tag comparison). I need to do some more investigation to be more definitive.
I've found that a change to the filename on the device causes no interference in sync - suggesting that sync is going just by match key.
I agree that Database.mpl maintains a file list, but I don't see evidence supporting your suggestion that the filepaths within are checked upon sync.
I'm going to to assume "The sync mechanism relies on matching certain values, one of them being filename" is not so - especially since checking just the match key is the right way to do it.
And since that gives me a temporary workaround - amend the device filenames post-sync, externally. Thank you, MrC and MC!
In any case, I agree it would be nice to be able to change the file name.
Can you suggest the best way for me to present that to the Dev's wishlist?