Stamps offers at-home postage and mailing for a monthly fee. customers are able to carry a balance on their accounts that allows them to mail packages and letters as long as there is a balance in their account. stamps has a button on its program that carries this logo, "to purchase postage, click here." following that click, another window pops up that reads, "you are about to purchase postage. once you click 'okay' below, you cannot change this transaction." why does stamps have the second pop-up button?