Why would you ever have to sign any type of agreement before you ever see the terms. When shopping for a car would you sign a letter stating that you will buy a car for ุꯠᇸ and hand them your money hoping that they give you a new BMW when they deliver to you a 1975 Pinto? No of course you would not.
For example, there may be soil contamination in which the buyer will not want to purchase the property and will safely option out of the non_binding contract. Or, perhaps the property is in a lot worse condition than originally thought, causing the buyer to negotiate a decreased purchase price.