Some providers would rather not deal with references due to competition and/or the time and effort required to research and reply that's not making them any money. They often screen other ways so don't depend on previous behavioral vouches themselves, and that's a commendable idea anyway, learning to be self-sufficient for safety and expediency when those ref requests don't get returned or might be coming from questionable sources.
I'm very reference-friendly myself. Seems like mutual cooperation would encourage a more secure, amiable environment for us all.
Not that the OP is a noob, but just FYI, every lady on the Houston Newbie-Friendly Provider List is required to be reference-friendly as a matter of necessity. http://www.eccie.net/showpost.php?p=...&postcount=378
One caveat, of course: The session must go well to EARN that vouch. A reference isn't an automatic right just for showing up. If some gents are having trouble, they may wish to reexamine their experiences. Were they discreet in their behavior making, arriving, and leaving the amorous assignation? Were they on time, clean (or willing to get that way with an immediate, uncomplaining trip to the shower), with proper donation in hand? Did they have to be prompted to pay? Did they try to negotiate once there? Did they overstay, become pushy, impatient, overly-aggressive, critical, or too nosy about the lady's private life? Asked for something not advertised or not applicable to the service/slot they requested and became offended that it wasn't/couldn't be offered ? Gents won't get a ref if they don't follow the rules and play nice while being naughty, as why would we want to green-light someone who may present a problem?
Also, after the appointment, a respectful PM from a fellow asking the provider if he can drop her name as a ref in the future, especially if it's been a while since the session and another lady will be asking imminently, is quite polite... and highly recommended.