I’d still call that self service, just putting something there to discourage the behavior.

I’m thinking of this more like going to a self-serve frozen yogurt place. I know at the end it’s by weight so I always get a more reasonable amount of soft serve and skip most of the overpriced toppings. If it was whatever I could fit in the cup, holy crap I’d be getting a small size cup and loading it up with as much as I could managed to.