I never noticed this before, but Craigslist puts a warning at the top of my browser window when I am looking in Craigsist San Antonio and viewing things advertised outside my area.
Avoid scams & fraud by dealing locally! Beware scam job offers involving payment transfer/handling, Western Union, Moneygram, wire transfer, cashier’s checks, money orders, or any request for your personal financial information (e.g. SS#, bank account #, etc)
It has a yellow background so it gets your attention. Pretty cool. Kudos to Craigslist.