How can this scam still work?

I am sure many of you are aware of a scam on craiglist and other sites. Scammers search for vacant listings, and then try to "rent" them to an unwitting renter. These people do not own the property and often don't even live in the state where the house is that they are supposedly trying to rent. I had a lady call me this week because someone had put one of my listings on craigslist and she saw my sign in the yard for sale as she drove by. She was certain it was for rent and I was completely sure it could not be rented as it is a shortsale preforeclosure property. She forwarded me the email from the "landlord" He even got a yahoo account with my intial and last name so he seemed legitimate. How do these people really get any money? They don't have a key to the property, they are asking someone to send them an application fee and deposit in promises that they will then mail a key. This just sounds like the most ridiculous scam because I can't believe someone would send a stranger money under such circumstances. I have changed all my vacant listings to occupied in the MLS and left them as vacant when agents call my showing service. Just another crazy real estate story...