I am a landlord and I tell my applicant to be wary of scams, whether or not they rent from me.
1) Check the online county records and verify who the actual owner really is
2) Make sure the owner is present with a drivers license ID to verify identity. Even if you're going through a management company, often the owner wants to meet the tenants. If the owner refuses to be present to verify identity, then refuse to rent from them.
3) Look out for a situation where it's "too easy" to rent and a lot of money comes out of your hands. For example, if the landlord or manager doesn't care to know much about you ... your background, credit, rental history, or job status.
There are good landlords out there. These scammer make me sick too. I am afraid for renters who are desperate in today's tight rental market.