You can and people do it all the time, what you are not allowed to do is say "sorry I can't serve you cause you have a different skin color", but you can certai

You can and people do it all the time, what you are not allowed to do is say "sorry I can't serve you cause you have a different skin color", but you can certainly say "sadly due to our terms we cannot serve you because we cannot serve people who are born in North Colorado because we get to much fraud from North Colorado". There is tons of ways to "not serve" people. Just try not to be an outright racist and you're fine. A business with a terms of service that you signed always says "Random Business has the right to refuse service for blah blah".