I sent nearly 2K via F&F for a component this year on USAudioMart who had 100% positive deals. I buy tubes on eBay with sellers who have 100% positive as well. I also bought tubes from a member here on Audiogon and he sent me the tubes to try before I bought them. All have gone off without a hitch. Reputation and trust.
2K is about my limit however, and anything above that would be risky in my estimation. Escrow service lawyers, if shown to be experienced in that work, does sound like a good solution.
Personally, I would trust a lawyer who was also an audiophile like moto_man as this trade is a community and, for whatever reason, I feel comfortable with others who share my interest in this hobby.

