I am changing Md5 with a button of my rapidleech server and i also add another small file (e.g a text file with "thanks"), but my files still get deleted.
I also tried something else once. I was cropping the last secs of a movie at the end where we see the actors names etc...
My files were deleted even then.
I think that if someone reports your files, they will get deleted for dmca reason no matter if you change md5 or add another small file.