If you conduct a research, you will learn that car rental companies cap the mileage per week not at every location and not for everyone. If you say that arrive by plane from other city and would like to rent a car at the airport, they may give you unlimited mileage. It depends on the city, of course. If it is New York, Chicago, or San Francisco, where there is a lot of places to go to, it is unlikely that you will get unlimited mileage cheaply, if at all. (Although some companies may permit unlimited miles as long as you stay within a certain region.) But if it is such a city as Lincoln Nebraska, where there is nowhere to go to, they will likely offer you unlimited mileage themselves (without imposing a condition of staying in the region). For the same price. Just to make you feel better that the wind brought you here.
Thus, the contradiction is resolved by renting not in the city of your residence but elsewhere. You do not have to arrive there by plane, of course. Arrive in your car, park it in the airport parking lot and have a wonderful vacation !
What, do you say that to resolve the above contradiction one has to know that somewhere it is possible to rent a car with really unlimited mileage ? And if one knew that, there would have been no contradiction ? You are right, of course. But most contradictions are like this: they exist only because we do not know something. And as soon as we learn it, the contradictions disappear. Thus, in most cases separation principles are pretty useless. While some piece of information is missing, all separation principles seem to be unsuitable. But as soon as we get it, contradiction disappears and there is nothing to separate !