If i’m meeting someone away from the house I usually aim to get their a bit early so I can note their car/reg when they arrive. Let them check it over then count the cash while they have a spin.
Maybe i’m being niave but i’ve sold over 20 bikes in the last few years, most of which have been from home and i’ve yet to meet anyone other than a really nice guy from on here, Pinkbike and Gumtree.