Craigslist/facebook is like an on line garage sale, where I expect to haggle as well. I just sold my 65 F100 on craigslist and I knew we would have a small price dance, but I'm not a dealer and the truck was a toy, not everyday transportation in a hot market. I got what I wanted out of it. Still, I emailed back the other people that had expressed interest so they would know to move on, just like you do. Its a courtesy to the potential customers. Some people will never be happy. Guy would probably haver complained about a few rock chips if you had sold it to him.
thats the one thing I'll give FB over CL, you can hit the sold button and it marks it as such for everyone