As a Scandinavian that sounds normal, and has been my entire life. In fact you don't need to buy gas to use the free air or water, it is just out in the open in a service cabinet or on the side of the building. (There is sometimes a sign that the water is only for cleaning your windows / mixing windshield fluid from concentrate, not for filling up RVs, and the flow is very slow.)

I'm curious, do they actually check that you buy gas in the US before letting you get those services?