Oh ick yeah I wouldn't either! But between the snakes, dogs, business, and family, my time away from my day job means I'm taking a "staycation" instead of a trip somewhere.
Can you give them two smaller dishes of water on opposite sides of the tub while you're gone so if one gets used as a toilet, the other should stay clean?
Maybe I do just have a sensitive nose, but when one snake has made a mess I know it as soon as I walk into the room. So, even my spot cleanings are thorough about removing all of the soiled substrate if the snake isn't on paper.