A couple of years ago I purchased a vintage instrument that I found on CL. The deal was done in person so no scam.
I posted a pic of the instrument on a music forum I frequent to share my find with some friends.
About three months after the purchase I received a PM on the music site from someone in Ireland wishing to know if I still had the instrument. Being cautious, I questioned the questioner. He sent me a link to a CL ad in Ireland offering the same model / year instrument for sale at one tenth it's value. I contacted the seller and he sent me pics of two different instruments one of the pictures being the one I posted on the music forum. As luck would have it when I replied asking which one was actually for sale, he indicated the one I owned. I messed with him for an exchange or two discussing payment method and shipping before reporting the ad and calling him out on his attempted scam. The ad disappeared but I am sure he's still out there trolling for victims.
I still watch CL and have purchased three motorcycles there, but all deals have been done in person. I wouldn't buy anything off of CL that I haven't got my hands on when the money is exchanged.