hi Nathan,
I have a post about this very same thing (not a banty and no eggs). I am wondering, too, what would happen if we left her alone...but my understanding is that unless there are fertilized eggs, that hatch in 3 weeks, it is a problem. Some hens apparently waste away because they don't eat much or drink much (and without eggs there is no end date). our girl seems unhappy and is definitely not thriving like she usually does because she isn't out and about.
We have been trying to break her by getting her out of the nestbox (or roost) whenever we see her going in (to avoid isolating her in a wire cage, no nesting material-just food and water, for several days) and it was promising over the weekend but today she was back and determined to brood.
I will look for any input from others (as well as how it's going for you) . Good luck!