On the same token, deleting the file from within AC deletes the ASSOCIATION between AC and the file, but not the file itself.
I agree w/ Bert, it's best to leave that file on the hard drive b/c you might need it and we all have OCD. It's a great therapeutic way to overcome the symptoms.
Deleting the file from within AC DOES delete the file itself if the file is not being "previewed" on the imported items screen.
Now I really only care about this for items that I think best to not have remnants of in a patient's imported items folder (items that have been imported in error). Otherwise, I might not be sure that if a patient gets a copy of their "file" it doesn't include a copy of a different patient's medical info.