I have also heard of this. 

I am also extremely skeptical. I believe it is a scam to get people to buy solar panels. The client would have to prove a profit motive for their schedule C. Who are the clients business clients? 

I did a google search and found 

with this link https://pcisolar.com/resources/save-money-with-the-federal-solar-tax-credit/ The result should tell you something  Did they sell your client the system?