Craigslist? What am I doing wrong?

There are risks when dealing with someone unknown. I'm sure the risks are very low but less than a month ago St. Louis news had a story about someone on Craigslist posting something for sale and someone contacted them wanting to meet them at a gas station to do the deal. When the seller drove up the guys were waiting to meet them and walked up to their car and opened fire on them. They did not know them, they also apparently didn't do it to rob them, just some jutjobs to shoot someone. The driver was hit but managed to get his truck in gear and burn rubber out of there quick enough that his wife and child weren't hit. Random shootings are on the rise in the US and nutjobs are using every opportunity to spread their terror. Am I saying only craigslist has this problem or is the leading website with this problem? No, but it is a growing problem. Does anyone remember Phillip Markoff?