That's good advice but people can takes steps to make legit out of town or out of state transactions. I'm in TX and I bought an expensive sports car I found on the Seattle/Tacoma CL. Paid with a bank transfer and had the car shipped to me. It took several phone calls, cooperation, and some trust... especially on my part. I had a buddy in the area who checked the car for me and I'd seen pics but I still had some doubts. When the car arrived it was much better than I'd hoped. I've also bought and sold rare and custom made car parts via CL with out of state partners. There are CL search engines for finding items on CL nationwide.
Every out of state inquiry isn't a scam. You have to use some personal judgment too. I wish I'd kept some of my CL scam emails. They didn't even make sense.