We have both volunteers and paid staff in our gift shop - the volunteers do not have shop keys or access to the safe. Our legal sees that as sufficient differentiation between the staff and volunteers to meet the legal requirements. 

Thank you! That is how we have our volunteers but unfortunately our legal wants to read the law conservatively so we are not allowed to have them anymore :( I tried to argue that pretty much every hospital gift shop has volunteers but we lost that battle. 

When I got a new VP from another organization a few years back, I went thru a similar situation with her. The concern she expressed as it relates to the FLSA is volunteers coming back later and suing for back pay because they did the same things as a paid staff member but did not receive compensation. I imagine this is the same reason for your legal team. I had to write up a list of all the duties of our volunteers versus the paid staff in the gift shop. I had this, of course, because we have service descriptions for all volunteer positions, and I had a job description for the paid staff. She discussed it with legal, and we were cleared to continue. There had to be a clear distinction of duties, with the volunteers having far less responsibility. Don't know if this helps since I'm sure you've done this already, but this is how we were able to plead our case successfully.