Comment by gnicholas

This is allowed in the US. But it's not like the surcharge is tied to the amount of rewards on the card, at least here. If you have a no-rewards card, you pay the same surcharge as if you have a upper-tier Amex. And since most places don't make it very obvious that they're charging a cc surcharge, customers generally don't even realize they're paying it.

I was not thrilled when I saw it on my receipt, after not being told there was a credit card charge. I don't mind a surcharge but it felt like a cash-grab because they didn't tell people (or ask them, which would be even better).