When I was in the hospital for an eating disorder a plastic container was fitted on the toilet with measurements, and my fluid "prescription" would be adjusted. The nurses would also use this to monitor whether or not I was actually drinking the water they gave me, and there was a nurse present in the room, with the door open.

This process felt extremely invasive. I would have killed for a toilet like what you describe, and I feel as though my physical/medical treatment would have been more successful.

(Somewhat tangentially, the food given at hospitals doesn't make sense for someone who has been nutritionally deficient for years).