I've always required RL information from potential clients, I would like the comfort of knowing who I am dealing with, a screen-name may help but just a simple membership to a site is not the golden ticket to see me. I have never had a problem with obtaining this information from the wonderful gentlemen I have met in the past and would not feel uncomfortable with someone who I felt was trying to avoid giving me certain information.
In my opinion, if you are dealing with a provider with a good reputation, great reviews, and screens appropriately you shouldn't have to worry about your identity being in danger because being careless with confidential information could harm her business as well.
But that is just my opinion.