Not most cars I've seen so far, but most filling stations also have hoses long enough to reach around the car, so unless you drive a battleship or a tank, it doesn't really matter.
There's a station near me that just opened. Pay at pump, pumps only on one side. 'Surely' I thought, as I pulled up, 'the hoses will reach the other side'.
They didn't. So I got out to move my hatchback car closer and angled so they would reach. I unhooked the pump and put it in my car.
You just didn’t see the indicator (it’s an icon somewhere on the fuel gauge, typically in its center).
I was driving for ten years unaware of this, before somebody told me. It’s easy to miss that the icon telling you “this is fuel gauge” also shows you which side to fill the tank from.
Do you have an example? Every rental car I have tried in the past decade had this. At least 10–15 different models from a variety of different manufacturers.
Note that most cars have a little arrow on the dashboard next to the fuel gauge showing which side the fuel tank is on.