Actually thought of that as well. It would be a great question to answer. I will post as soon as I get the answer. Sadly, one recruiter told me volunteer exp doesn't count because its not paid RN work. Maybe it will count if I was performing duties as an RN with an evaluation from a supervisor.
I think one of the best reasons to volunteer is so you can meet nurses and nurse managers. Networking is invaluable. However, I found that many times it is difficult even to volunteer at some facilities.