However, I have heard horror stories from other people saying that there were wholesalers who swindle unsuspecting home sellers out of their well deserved money.

It's about short sale flipping and the "evil short sale flippers" who illegally and unethically make money from the poor, unsuspecting and disadvantaged lenders.

About a week later they call the unsuspecting landlord and say their transfer got canceled or some excuse like that therefore they cannot go through with the lease.

The prisons also release predatory perverts, violent criminals, etc. that should never be allowed around unsuspecting people, so use good judgment!

They just milk a property for years, and then unload it on some unsuspecting schmuck.

You seem to think I'm some sort of fly by night vulture preying on unsuspecting owners.

He can show you how to buy slums for ten grand in the hood and sell them as beautiful turnkey 50k homes to unsuspecting out of state investors !

In my case the lot was a strip adjoining my land that had been dedicated 70 years ago for a private drive to access several lots behind mine built on 65 years ago.The county would routinely sell this strip for back taxes (its not even on my tax bill) and unsuspecting buyers would find out;1 The parcel isn't big enough to develop2 The parcel was dedicated as a drive (can't be changed)       As for your parcel under a structure I would think a survey would be required and then see the rules on adverse possession in your locale, because that is what someone might claim against your potential claim.   

That is the difference between operating honestly or being an unlicensed broker screwing over unsuspecting sellers.

This has never happened to me, but I have heard stories of people getting your lock code and then pretending to be the landlord to another unsuspecting tenant and telling them they can move on in after signing an online lease and wiring a "deposit" to them.