Not only is it happening from third party sites, craigslist, etc The Greenville Association of Realtors is not doing well at having a properly displayed database of available rentals, the property management companies do not want to work with Realtors and there is not one central location to find out what is available. Coming from a market that has a streamlined rental inventory system I feel Greenville is behind the times and needs a solution, at least that way you could cross check information and the scamming might become less frequent.
Allan is right, it is becoming a VERY common scam. People have actually gotten to a point of giving first and last months rent, only to find out the person they were talking to had nothing to do with the property.
Have had the same problem with a Short Sale Condo of mine(322 Richard Court in Pomona, NY). For Sale only and a Craigslist scammer identifying himself as the owner and living "overseas" is renting for $900(worth at least $1600 if it was for rent). Problem is nobody will make the effort(authorities or Craigslist) to look into it. Thank you for the post