This is an interesting case where a deposition subpoena duces tecum was quashed because it sought records created by someone other than the recipient of the subpoena. Because the recipient could not verify, under oath, the elements of a business record, the subpoena had no force.
This case has potentially immense ramifications for discovery - it means that if a party has a copy of a document, one cannot get it by subpoena, even if it is the only document in existence, and even if the author - someone who can authenticate it as evidence - is a party to the case.
The potential for abuse is tremendous - any party fearing discovery could simply send their files to a third party to hold. It is unlikely that this is what the legislature intended.
There are a couple of alternatives. Perhaps the party holding the document must appear for an oral deposition, and bring the document. Though the document would not be authenticated as evidence, at least it would be discovered. Another option would be to seek an order that the document is really in control of the author, and force the author to obtain it.
Either option would drive up the cost of litigation -it seems more rational to simply agree to produce the document without the authentication, and for the party serving the subpoena to accept this.