Scams are everywhere. I have had to re-list computers on eBay several times, after people would use the buy it now, and then try to get me to use PayPal and send the item to an unverified address in some small country in Europe. Even after stating I don't do international shipping.
Same with Craigslist. Craigslist has local listings all across the USA. I often wonder why someone in Pennsylvania wants me to ship them a phone on the other side of the country. Not like they don't have local listings offering the same items in their own area. Not to mention if they are willing to pay more than your asking price, they aren't looking for the best deal. Just the best scam.
When it comes to Craigslist I am always careful to meet in a public place. Cant tell you how many times I was going back and forth with someone negotiating the price, deciding on a location, and then silence. They just disappear.