I’ve had mostly good luck with Craigslist. I’ve bought guitars, amps, and sold guitars. The only odd interaction I’ve had was once a guy was selling a contoured style Fender Tele/Strat case in mint condition for $35. I didn’t even really need it for anything at the time but it was a steal. I agreed to come to his house that day with cash. When I got there an older gentleman opened the door. He let me in, but was very unpleasant. He asked to see the money, which I had. Then he said “Wait here”, and walked away. As I stood there I looked into the next room. There was beautiful Dana Bourgeois acoustic guitar on a stand. It looked like a museum piece. He comes back with the case, and we exchange cash and case. I then asked him “Is that a Bourgeois guitar?” He says yes, and I mentioned that it was my older brother’s dream guitar. He said “good for your brother” and about shoved me out the door. He made it quite clear that our interaction had concluded. Another time I bought a guitar and picked it up at the guys house. He was sitting in the living room playing the guitar I came to buy. He was tearing it up. He didn’t see me at the door, and I didn’t knock or ring. I just stood there and listened. He was amazing. When I got inside he offered me the chance to play it on this killer little boutique amp he had in his living room. But it was like I was embarrassed to play in front of him. He was that good. I just said I listened from outside. I know it works.