Just another example of the writer's inconsistency. It's so prevalent, it gets to the point of hardly worth mentioning.
I saw a commercial for Finish dishwasher detergent saying you should run your dishwasher every day, full or not (BS), and it reminded me of Emily telling a maid not to run the dishwasher when it wasn't full, yet when Rory is snowed in there she acts like she doesn't know how to use the stove. Yeah, I'm sure Emily is regularly checking how full the dishwasher is. (Not)