Maybe not quite the same thing, but I recently won an innovation challenge for improving public bathrooms.
I started with what actions people take that make the bathroom as disgusting (pee everywhere, vomit, shoving food in the walls, etc) and then determining defensive mechanisms from there.
I like the stealth treatment you apply to the loo to reduce edges. Without wishing to imply my own bathroom needs a clean this would actually be handy in people's homes too (even though generally people are less wayward than they are in public loos)
I started with what actions people take that make the bathroom as disgusting (pee everywhere, vomit, shoving food in the walls, etc) and then determining defensive mechanisms from there.