Maybe not the best anology, but restaurants pay a % fee to the CC companies everytime you use your CC. They don't tack it onto the meal bill.
Wanna bet? You just don't see it itemized. Just as companies don't charge you extra to pay on account even though 2% may default into bad debt. It's all worked into the prices.
If someone wants to tack on the 3% I have no bitterness, as long as they're decent enough to tell me up front.
And then I'll deduct 39ยข for the stamp when paying by check.