I personally would not buy anything from somebody that only had a couple of posts on this site. I want to know his history before I send money. Having said that, I've sent items out to people before the money was even sent. They probably had the item before the money got to me but I trusted them and they found they could trust me.
I'd also tend to be more trusting of a person that I knew had the same gun interests that I do and was someone I'd been around enough, on this or similar sites, to know they were a stand up kinda guy.
I guess if you don't like the conditions of sale, you can discuss it with the seller and if you don't like it, don't buy anything.
I've never been stiffed for any amount of money so maybe it's good judgement or maybe I've just been lucky so far.
I can say there are a handful of guys on this site that I would not hesitate to send money or an item to without having received anything from them, no matter the value, and I'd feel confident that both parties would be happy with the transaction.
Shoot, I keep sending Kirby several thousands of dollars tied up in a gun and trust him to send it back. Sure hope he sends the last one I sent him back to me.