Just wondering when "Removing a photo from the catalog" running OSX could you Label the selected photo with an appropriate colour, or add a specific comment as you can using "Finder". This would greatly help in manipulating our files outside of Lightroom.
Generally, Lightroom does write back to the original files you have catalogued. There are exceptions, of course, but they are related to maintaining communication between apps.
Anything Lightroom does to satisfy this request will have to change the actual file, and not just a file reference in the catalogue. This would be a piece of metadata that would have to be checked for and possibly reset, when any file was added to the catalogue, and then set on removal. This is just a bad idea.
You would be better off using a plugin that writes out custom metadata that is saved to the XMP block (or something) and use that.