One of my cats absolutely refused to enter it, and did his "business" next to the litterbox instead.  The big guy flattened it, and a couple of others hated it so much they made a point of spraying it and trying to wipe their butts on it.  Needless to say, it ended up in the garbage.  It's not that these cats won't use a covered box -- they will and do -- they just really, really hated this tent.