I don't have a Sony and no interest in hacking my Kindle so I don't use the plugin and hence haven't been paying close attention to what the problem is attempting to be solved. I just saw a suggestion of using the calibre book id to attempt to identify something on the device and raised the point that in general that is not a good idea. Imagine a user who has a scifi library and a fantasy library. They then find some of their covers get overwritten, and don't understand why.
Now in the big scheme of things it probably isn't the end of the world in this particular case if it just concerns cover images, but imho you are better off finding an alternate solution that doesn't have such an obvious potential bug. What that solution is I have given zero thought to for the reasons above, I have my own plugin problems to solve...
