If a lady doesn't have reliable reviews, I'm unlikely to "TOFTT" (Take One For The Team) by seeing her unless there is something special that pushes my buttons. I don't have a typical hourly donation just burning a hole in my pocket, whimpering "Spend me now, dammit!".
I'm willing to provide some basic information as part of screening, I have local references, I've joined up with P411, and I've got an established presence on the TER message boards. I'm perfectly cognizant of the risks a lady is taking, and I'll do my bit to minimize them (while protecting myself as well). In return, I expect to see either a reasonable attempt to provide information on her part, or the aforementioned reliable reviews, or something to compensate me for the risk of fraud, like an "introductory special rate", or a connection with someone who is a trustworthy part of the local scene, such as either a reputable agency or partnering with a reputable independent.
I expect her to have done her research, and to ask rates that are comparable to what others are asking for similar service. In the DC/Baltimore region, FBSM service is typically $200/hour or less; if her asking price is $300 for an hour, I am going to expect a full-service experience. If she won't tell me how much her hourly rate is until we meet in person... I won't book, as that smells like a setup to me. I feel like I've gone out on a limb somewhat by offering up my screening information, my references, and registering with a service; she needs to be willing to work with me a little, and give some information. It doesn't have to be explicit enough to qualify as a letter to Penthouse, but being excessivle vague makes me suspicious that I might be reading an ad for a "Oh, you're just paying for my time, and if you want to do anything illegal, I'm going to skedaddle with the money right now" scam.
I generally assume that the rate listed in a provider's ad is her active one. If I find another one listed somewhere, I'll ask about which rate is the current one, and let her know where I found it. I don't mind her checking the envelope, although I'd prefer she didn't make a big scene of it, and doing it while one or the other of us is in the bathroom is a gracious touch, I think.