Stupid question, I know, but what damage is New York claiming that Trump did to the state?
Nothing. Overstating the size of a property usually leads to higher property taxes.
A bank, were a property be used as collateral for a loan, should do their due diligence to confirm the details of a property. The same goes for a buyer to a property.
That being said, commercial properties are especially hard to perform a valuation as one is trying to project income and losses in an ever-changing economy.