The new language does relieve uncertainty for Visa and MasterCard by clarifying that the measure wouldn't restrict the fees that the debit-card processing networks charge to banks.

WSJ: Merchants Win Debit-Card Fee Battle

The fees credit card transaction processing networks charge merchants for each swipe of certain debit cards have been limited since the regulation change was enacted last year.

FORBES: Credit Card Users May Pay an Additional Fee

The refund typically comes as a voucher from the carrier and some charge a processing fee.

WSJ: Summer Travel��Where the Deals Are ��and Aren't