Add functionality to help prevent upload of duplicate files

Great module! Any chance it could be enhanced with some kind of configuration option to help prevent duplicate files from being uploaded by a user?

Example:
1. User 1 uploads photo
2. Filehash creates and stores the hash of the file contents
3. User 2 should browse for existing photos to reuse (media module) but is lazy or doesn't know how so they attempt to upload the same file as User 1.
4. User 2 is initially prevented from uploading file, provided feedback in the form of a Drupal error message perhaps with information about the identical file that was already uploaded and given the option to use the same file already uploaded by User 1 or can override and upload the file again.

Alternatively, if this module could store the filehash in a field, the field validation module or clientside validation module (or others) could be leveraged to provide the uniqueness check and feedback. I attempted to accomplish this by using the token provided by Filehash and inserting it into a text field using the "default value", but Drupal 7 doesn't support using tokens as the default value.

Thanks!