A woman shopper was injured when she slipped on the tiled foyer of a supermarket, which was wet after rain. The defendant argued that it wasn't responsible for the slippery condition of the floor, and that it owed no general duty of care in negligence. As it had mopped the floor to minimise danger to customers, there was no unusual danger that would give rise to a strict liability on the occupier. How do you think a court might assess the defendant's claim of no liability