BMW owners FSBO-ing their cars are targets. Somebody was FSBO-ing his M3 in Florida and ended up dead in the trunk. In addition to violence, there's also forged cashier's checks, and various Nigerian Prince scams. There's a guy on the G30 board who got all sorts of aggravation trying to sell his old 328i. He was asking too much for it. That seems to really bring out the predators. He finally sold it to one of the national, on-line used car sellers for a song, and he vowed to lease BMW's from here on out.
I've never traded in a car. I've sold twelve over the years. Nine went to friends, relatives, or co-workers. Oddly, the car I had the most trouble selling was an E46 M3. Networking didn't work, despite having ten people on the waiting list. But, putting it on BMWCCA's website's classified ad board got it sold in twelve hours, and then I got another 200-300 inquires. The buyer was 600 miles away. I had a bazillion SWA miles and I was bored. So, for an extra $500 I delivered the car. He sent me $500 up front to cover my trip. We met in the parking lot of a Wells Fargo branch, went inside. He withdrew cash and I deposited cash. He's now one of six people on the waiting list for my 535i.