Fear of Floating

The Washington Post has a good article on an interesting email scam. 

Typically, here's what happens: You advertise a car for sale online. A fraudster posing as a buyer responds via e-mail agreeing to purchase the car for the asking price...

Next, the scammer persuades the buyer to accept a cashier's check or personal check for significantly more than the agreed-upon price. The excess is allegedly to cover the cost of shipping the car abroad. Or the check's too big, he claims, because it had already been cut for a car deal that fell through. Or the buyer simply apologizes for the mistake.

The key to the scam is duping the seller to deposit the check and, once it clears in the seller's account, return the excess money via an irreversible wire transfer, such as Western Union.

Now what always confused me about this scam is that it seems very easy to avoid.  Just wait for the check from the scammer to clear, right?  Wrong.

The scam turns on most people's misunderstanding of the check-clearing process. Bank clerks and managers usually aren't experts at identifying counterfeit checks. So they deposit the check and tell the seller it requires 48 hours to "clear." Then the money appears on the seller's account statement and can be withdrawn.

Most people assume that means the check is valid. But the real check-clearing process can take weeks. Phony checks generally aren't nabbed until after the seller has wired the overpayment to the scammer. And after the wire transfer is picked up, it's gone.