In my country, the law says "When the owner of a seized hard drive asks for a copy of his hard drive, he/she shall be provided a copy of his hard drive".
In terms of evidence integrity, the word 'copy' refers to forensic copy the seized hard drive. Normally, as a computer forensic examiner you make a forensic copy of suspect hard drive in E01, raw, etc formats, however if the owner of the hard drive asks for a copy his hard drive for practical reasons -such as he might need the copies of some files and folders for his business-, then an image file in forensic format like E01 will not be good for the owner, in other words, he has to buy Encase and learn how to use it.
So, how do you deal with this situation? Do you provide the owner one forensic copy and a non-forensic copy if he wants copies of some of his files for business?
A clone (copy) of the original is what most "non-forensic" requests generally refer to. It is of no use to give a forensic image to a lay person, unless they have indicated that they are hiring a forensic expert. Just make sure you document matching hash values between what you seized and what you returned.
If I was the owner, I would expect a "physical" hard drive with a copy of my hard drive. That way I just plug the one you provide back into the PC.
Think about it. Even if you give me a Ghost or WIMS image (which are not considered forensic copies), I would need to buy additional software and a hard drive to get access to my data.
Laws are never clear, and are subject to interpretation.