I used to travel through the Memphis area a lot and I have used a Memphis provider or two as a reference for other providers in my home town. However, I have ALWAYS spoken with the lady whom I was asking for the reference so that I could get her permission and give her a heads up. I didn't want her to think that it was some sort of entrapment scheme by LE or some other type of scam that could turn out badly for either of us. If you want to give a provider as a reference, ask her permission and tell her who will be calling or e-mailing! That makes it safe for everyone concerned.
Charlie