When placing an ad you usually do get several "off the wall characters" responding. Ignore the obvious loose cannons and use your street smarts in dealing with the others. Quickly let them know that you are not one to be intimidated.
Two recent experiences I had selling on FaceBook Market Place:
1. A very used 1998 Toyota Avalon. Over 600 responses. Too many for me to review so I picked the closer to my home. (One of the first wanted me to meet him at a public place 3.5 hours from my home, for an $800 sale!)
2. I
sold my 2001 Jeep Cherokee with ZERO RUST and near perfect condition in every other way. I was selling for top dollar for this vehicle. Many people responded offering me a fraction of what I was asking.
I had it parked in my driveway with a
FOR SALE sign. Many tire kickers would stop mostly to admire it and let me know they had owned one just like it several years ago or people again offering a fraction of what I was asking.
Then a guy stopped and I went outside to greet him. He gave it a very quick look over and asked me my price. He then said he knew he was going to buy it because he felt good energy when I came out of my house. He got his wallet out and handed me a 100 dollar bill and said it was
sold without having looked under or in it or anything. I said I was going in to get the keys and when I came out he was gone. No name, telephone #, or anything was I given. Four days later he showed up with cash still not having looked it over. He told me then that he was in the "Fifth Dimension" and he thought I was too. We went to the magistrate to make it legal. I gave him the keys (him still not having been in it or even running the engine). He left the magistrates office and I didn't see him again while the Jeep continued to sit in My driveway for almost a week. Finally I looked outside and it was gone.
Bottom line, be prepared for the nuts, but do use your street smarts. Weed out the characters and give them more to fear of you rather than you of them.
I grew up amongst drug addicts, thieves, thugs, and members of infamous biker clubs. Survival is dependent on letting them think you are on equal footing with them. If you do this you will be OK. Scammers and the the less than scrupulous look for easy marks. They avoid those that do not appear vulnerable to their schemes. Unfortunately, reality can be a sad state of affairs.
Also, using this site as a venue for selling a glass trailer should bring you more focused and ultimately more relevant prospects than the crackpots you may encounter on Craigslist or FaceBook Market Place.