I did some following up with personnel at the state attorney general's office. Subpoenas can be signed by anyone (even a monkey can sign it). It carries no legal weight unless it is signed by a judge. Think about it... you and I can sign subpoenas, too!
I am at this moment looking at a subpoena that looks official and I was formally served this subpoena (had to sign for it). Sent it to Physician's Insurance. Guess what?

The subpeona carries no legal weight in the State of Washington. If I were to respond to this data due to this subpoena would be INAPPROPRIATE disclosure. I'll be happy to send you a redacted FAX of this supeona.