It would be handy (for me at least) if, when converting a batch of filenames based on the tags, when the program detected that a file of that name already existed, the user be given an option of using that filename again with say a "_(2)" appended.
Then the user could compare the renamed files and decide if they were the same or different versions, etc. from the ones that already had the intended filename.
An alternative action might be to have those files, that would have had the same name, to be flagged somehow, eg. colored text, at the end of the batch conversion. At least this way the user gets something for his/her effort of selection. Currently the files are overlooked and it is up to the user to search for them again.
I hope that is understandable ! Sorry, I am not used to describing such things.
I wish you all the best,