Getting back to the question at hand: until and UNLESS the attorney retained by the carrier files under LC 3755, that attorney does represent both the IC and the employer, and other than the Canton Poultry case, I have never heard of that having been done, and have never - despite having been employed by Stockwell, the firm in Canton - as well as other "big name" firms, even heard of it being used, despite the fact that under many situations, it would be very, very wise for the attorney to do so; but subject to very critical review, and approval by the carrier, and, in my never too humble opinion, by the employer, who may be understandably upset at being abandoned, so to speak, by the attorney and the carrier; in many cases it has been my experience that the carrier would be extremely upset if the attorney did such a thing without their approval and the resulting possible loss of their insured as a future client.
So if the issue is, can you take the deposition of the insured business owner and if you do, can that owner claim attorney-client privilege as to communications between that owner and the attorney hired by the carrier, the answer is "maybe, if there was a filing by the attorney/carrier under LC 3755."
HOWEVER, that does not end the discussion! Let's suppose that the owner, for example, asked the carrier about terminating the employee in part because of the comp claim having been filed. That would still be attorney-client privileged if it had been done before the 3755 filing; there could be other matters which would come under that privilege and each would depend upon the facts.