I was reading this excellent guest opinion piece by an Oregon attorney bidding farewell to the GOP after 25 years, and noticed that one of the GoogleAds in the ad bar at the bottom of the piece was for "Senator Bill Frist, M.D." clicking through the link brought me to the website for VOLPAC, aparently Frist's Political Action Committee. 

While there is a form to register as a "volunteer" there is no listing of any actual volunteer activities, so I'm guessing the name relates more to TN being the "Volunteer State".