I disagree.
If they are able to incorporate the rule of one ball per round/per hole, they should also incorporate a script to keep on using the original ball for said round/hole, and make it expire once this is over (otherwise they're forcing us to break the rule they enforced, right?)
I don't see why they don't do it, doing so doesn't gain them any more revenue...
Having said that, they don't exactly hide from you how many balls you have left, or how long each will last, and if people don't want the ball to change, they should either buy more, or switch it themselves before the game starts