Well, no, but you would ask your family doctor for a referral to someone who offers different services (ie. ob-gyn, urologist, oncologist). We're not all cookie cutters of each other, offering the exact same experiences. If a client wants to see another provider, I'm more than happy to provide a reference because:
1. It establishes contact with another SP, and encourages that SP to give references him/herself. Pay it forward!
2. It shows that the client is willing to go through the reference procedure. I just don't understand why some people have such a hang-up about them - they ensure everyone's safety. Reviews/recommendations are a way of clients to refer a lady, if you think about it.
3. Refusing a (good) client a referral makes me look like a jackass, and probably ensures that he's going to think twice about booking me again. Possessiveness just doesn't mesh with this line of work - I'm certainly not exclusive with a client, so why should he be exclusive with me?
4. If a petite brunette is what has you hot and bothered right now, I'm not going to be able to fulfill that desire. Plain and simple.
On that note, I appreciate a note from the client in question asking if it's okay to use me as a reference. Not to ask permission, per se, but it's a sign of respect. You wouldn't give out a work reference without giving that person a heads up that they may be getting a call.