Haven't read through every comment, so don't know if it's already been said, but why not just look at the date that the file was created?
I have a feeling that the chance of them just turning in the 'end result' file would be bigger than the chance that they're copying it into a new file.
The linux distribution is still called Arch Linux so it would be weird if it said that they ported Arch BSD to FreeBSD
Haven't read through every comment, so don't know if it's already been said, but why not just look at the date that the file was created? I have a feeling that the chance of them just turning in the 'end result' file would be bigger than the chance that they're copying it into a new file.