I think that's pretty much what JM said happens. I can't remember now where I saw it or what he said, but I think he suggested not using the maid or not using the fish tank.
This was mentioned to Maxoid Tom (aka HatedMaxoid) over on one of the NL threads here about the upcoming patch. He thought it had been fixed in the previous patch, but it was broken again in Uni.
Yeah, it was me that mentioned it in that thread and she's still at it.
I put the fish tank underneath the house when she comes (moveObjects on) so she can't get at it but I don't always remember and then find her standing there washing away constantly and NOT cleaning the rest of the house.
ooo - now I'm an asinine airhead instead of a tasty tourist.