"That's probably (Discover and American Express) reasoning, to differentiate themselves," Roy said. "I wonder if (retailers) are just kind of waiting around to see where the chips fall, because they're being quiet. I don't think anyone knows what the impact is.
"The retailers can always change their minds. They might be playing it cool right now, but down the road they could change their line of thinking."
Roy said the concept is similar to retailers or locations that give discounts based on the consumer using cash instead of a credit card. This is sort of a reverse method of that. She said she doesn't expect there to be much of an impact on larger retailers, but smaller mom and pop stores could be a different story.
"I could see mom and pop stores doing this, because that 1 to 4 percent could really go into their profits," she said.
She said merchants who don't want to post the signs announcing the additional surcharge can simply adjust their prices to reflect that amount.
"Really, we're being charged anyway," she said. "Many times (the charge) is put back into the price of the products, so this is just a way to present itself and be more transparent is probably a good way of putting it. Sometimes the retailer might put the charge in the price anyway.
"I think the really important part is the signage at the point of sale, the store entrance, online, as well as what the charge is on the receipt. That's the good part of the legislation."
Roy said she's proactive when she shops as being informed is a customer's best protection.
"The advice I would give is to ask the question," she said. "Whether you want it to be a part of your routine every time you check out somewhere, ask 'does it cost me more if I use my credit card?' and the flip side of that, 'do I get a discount for paying cash?'"
More information on this and other potential unknown credit card rulings can be found at the website knowyourcard.org.
The 10 states that have state laws restricting merchants from surcharges on credit cards are California, Colorado, Connecticut, Florida, Kansas, Maine, Massachusetts, New York, Oklahoma, and Texas.