In my experience most times (not all) the girls want payment upfront because you are either a first timer at that particular venue or a first timer with them, once they get to know you for awhile and feel comfortable this changes. An example would be my sessions with Bella, I've seen her a few times, and she never asks for anything upfront because she knows I won't pull something, so she's at ease with me. A few months ago I saw Bella and forgot to stop by an ATM, I was completely embarrassed, I excused myself for a few minutes to run to an ATM and Bella and Vera were cool with it. It's all about comfortability.