I always put the donation in a birthday card and sometimes pick up a little something from the ladies "spoil me list" to go along. I figure if it is illegal to exchange money for sex, how would one be able to prove that sex is indeed what the money was for if it was clearly part of a birthday gift?  

primarily if meeting in public.  In private I usually just leave it in an envelope unless I know her better.  I do generally tip 20%

It's like claiming entrapment. In theory it's possible, but in reality it's difficult to convince a jury or a judge.  As evidence, when the police asked you for the name and the birth date of your birthday girl, why were you not be able to provide it to them?  Why are you in the habit of giving gifts to complete strangers?  It's a myth.

I do the same but not for the whole "illegal" aspect since the chances are basically zero a well vetted provider is involved in some sting.  I do it to garner good favor in the event I choose to repeat a date with her.

I didn't know there was any myth. Honestly until I asked here I never heard of anyone else doing it.  

And to be a bit more clear..... I'm not actually anticipating being questioned by the authorities. I do it because it adds a fun twist to the entire event. I guess essentially I'm creating plausible deniability in my own head that the encounter is anything illicit. When I say "how would one be able to prove" I really mean any imaginary third party, not real life law enforcement. Just an added layer of fun for me. Wondered if others did the same or perhaps had other scenarios? Does that make more sense now?  

I think I chose the wrong word. Should be "illicit" instead of "illegal." I never meant to indicate I ever actually expected to be questioned by police.  

You may recall a couple of years ago a well known agency was shut down and the management, providers, and several clients were arrested.  The apartments had hidden video cameras installed with the permission of the landlord, which recorded all the activities.  That being said, the videos were later ruled inadmissible, because the prosecutors only had a wiretap warrant, which didn't apply to the video cameras.

I remember that . I also remember something about guys being picked up later at their homes and places of work?