I believe most seller in CS are honest, since we are not like those "un-reputable" for out to con people.
I met a real nice seller ytd to get a lens from him. I bid it about 3 weeks ago and he reserve for me since I have am in exam period. Then he also teach me how to test the lens since I do not have much experience.
After I tried out the lens, he took over to test the lens to make sure that it works on my camera.
I believe its good to go to the B&S section to look at the thread and if the seller is good, most likely the previous buyer would "up" for him.