I still don't see what is wrong, it prevents congestion, it is fair and equal for everyone. And if they can charge based on license number, it is no more difficult to implement.
Isn't the goal here to have less cars in the zone? Thus goal is preventing them from entering. And giving everyone equal chance to win right of entry is fairest model.
Shooting and killing a random 1% of drivers every day would also prevent congestion, and is fair and equal to everyone. There are other considerations though.
China has an odd-even solution to this - on even days, cars with even numbered plates can drive in the city and the same for odd days. They did this for gasoline rationing in the US back in the 70's as well.