I mean from anyone. Providers especially, but other mongers too. Unless you become such good friends with another monger that you are introducing them into your normal life circle, there is no reason to not maintain your identity. Why make someone else have to remember which name to use at a party. Keep it simple. 1 identity for all hobby related stuff.
I don't use agencies that require verifiable personal info. If references aren't good enough for them, then I move on. Of course, that's easy for me to say. I don't use agencies in general. But I have been to at least 3 incall agencies (1 massage only, 1 massage + extras and 1 completely full service) that did not require my personal info.