Hi Duffinvt. I am just responding to your query about having piggies on a sofa. Gizzy is used to being on the sofa and on the bed. She learned from day one and seem to test her boundaries only now that she has been used to it for such a long time. I think it is build into their skittish nature to check things out so I think chances are good that they won't fall off but just keep your eye on them. They will also tend to run away from the open side of the sofa if you are trying to "catch" them I am sure.