Actually they are not. Merchants are protected from providing any information on the fraudulent use of business debit cards. Master Card secures the charge to the merchant regardless of abuse. There is no way to reverse these charges if they are made on a business card.
There is an added layer of protection if the business debit card holder signs up with MasterCard for a special hidden password available through their secure card program. This simply precludes false charges by less sophisticated fraud.
Once a felonious charge is made on a business debit card it cannot be reversed. The consumer protection law recently passed by Congress protects individual consumers. It does not protect businesses.
Thanks for the correction.
Mark