'what spiders? what baths?' as Dr johnson once sort of quipped when being pressed by Mr Boswell in a well known coffee shop deep in the heart of London Town.
Some spiders can climb walls. But even your grubby grey green greasy bathtub is too steep a climb where your average domestic spider, (as opposed to more exotic breeds with all sorts of grippers on their tootsies) just cannot get a grip and sustain the effort all the way to the top. The more shiny and new the bath / sink, the more difficulty these little darlings have in reaching for freedom.