From the Florida Land Title Association:
One of our members reports having been hit with a new fraud of a type that could easily catch any of us. A couple left their closing with a check for their proceeds. A couple of hours later, they returned to the closing office with the check and asked for a wire transfer instead. The closer voided the check and processed the wire. Unfortunately, the couple had used their smart phone and deposited the check before returning to the [closing office]. Even normal "Positive Pay" protections would not have caught this as the original check had already been approved for payment.