Yes, there have been some horrible situations, murders etc, however, when you look at the stats of the number of transactions, the number of crimes, I would bet a real nice cup of coffee that it is less than the random crimes.
Meeting in a PD parking lot is a nice touch, considering a 911 call will reap action in about 10-25 minutes, if you yell in the parking lot, it may only take 5 minutes.
I have sold and bought on CL hundreds of times. I just take normal cautions. You know, lights, hidden cameras and 5 friends with semi auto weapons hiding around corners.
Just kidding on that last part.