Yeah, I have those concerns from time to time, too.Edited for clarity.
She backed out and regurgitated in front of the box. Yes, it would have been convenient if she had just used the box. Or maybe not. I'm not sure how much litter I have left. And I also don't want to risk her tracking barf litter out of the box. On the pee pad is good enough for me. That'll do, Donkey!