* How does the toilet know that everything is clean? With toilet paper, you can just wipe with new toilet paper until there is no more residue.
* What is the algorithm for the toilet's spraying? Does it end up spreading diluted feces around, or is it careful to spray outward-in?
* What happens if feces end up on the nozzle? Is there some kind of auto-cleaning mechanism? Otherwise it might end up spraying old feces back to me.