I have never had a person in my home that I regretted inviting in. Generally, the kind of people that buy used high end HiFi are not the high risk type. How many crooks even know what an Audio Research Ref 6 SE even is?
I NEVER let someone over until I've had a nice long talk on the phone with them- including some topics that help me evaluate their character. You can tell a lot about a person by their word usage, attitude, personal transparency, and knowledge of the item you are selling. If those planets don't align no deal.