Unless I have had long(ish) involvement with a seller I just don't take the risk anymore.
I mean in general on here for example I have had chats with RR within a topic.
For example, and if he reads this its not personal, I recently turned down an item after showing interest because 1, I had never ever seen or spoke to him/her and 2, his post count was low. I was only going to save £15 so I decided it wasn't worth it.
I didn't realise until after I had shown interest.
That goes for buyers too.
Its like buying on ebay with zero protection.
I also think posting once you have sold/bought something where and when you are going to meet as potentially your meeting someone who is going to beat you up and steal your cash/parts/car etc etc........! I know the person could have been lying about his/her identity but at least there is an IP address trail.