If I play with the food, then I will not be going to use the toilet. And if pee or poop is released, then it will involve the need for diaper-wearing. With messy eating, the potential of requiring that I wear a bib. If I act like I need to be returned to diapers, for feeding time, then those diapers will potentially be used.
Furthermore, if the diapers are on, I will use them fully, unless the dominant says otherwise. This is a roleplay scene, built around diaper domination. If I am in diapers, I do not need to go potty outside the diapers, with potentially imposed full use of the diapers.