Legal Question in Real Estate Law in New York

The owner is permitted to remove any item of personal property or fixture that is not listed or specifically excluded in the contract as being sold with the real estate. He or she may do so provided that closing (or delivery of possession pursuant to a post-closing possession agreement) has not yet taken place.

In English: if they stole the stuff after the deed was delivered, then they committed burglary and trespass. If they did it before the deed was delivered (while the closing was taking place) then no crime was committed but the seller deserves to be outed in the locality as a sneak and a thief.