One of our local marine title companies reports that in the last two
weeks they have receivd two counterfeit cashier's checks. One was for
$470,000.
In both cases, the party supposedly purchasing the boat presented the
check for a substantial amount over the agreed upon selling price and
requested "cash back at closing" so that the buyer could arrange pay a
trucking company to haul the boat cross country.

Looks like a confirmed wire transfer is really the only way to go.