Well, I have to agree with the "Craigslist Syndrome", though I have always had people come to my garage to meet me, I have still been stood up.
It's the ones that say they are on their way and will be there in a 1/2 hour etc. and then they don't show up or even give you a courtesy call. I would never tell someone I would meet them and then not show up or call. I don't like it but I've accepted it's going to happen from time to time, it's all part of being a seller.
But the ones that actually show up have always bought the part and sometimes they end up buying another part at that time or at a later date.
I know a lot of people do the meet somewhere thing and that might be the only option they have for security or other reasons but I have found for me, especially when I am selling a expensive race part that the buyer is far more confident after meeting me and seeing the work I do and that I'm not just someone selling a part of unknown origin out of the trunk of his car. I have also found doing this I usually get my asking price even though it is ($--/best offer).
And even though I live in a good area on a dead end street with a neighborhood watch and half of my neighbors are retired and home all day, I still take security seriously and have quite a few measures in place because of what I have in the garage.