Sharp Edge was always a bit slippery when wet, and lethal when crusted with ice.
Last year in Mallorca, I went down through the notorious Torrent de Pareis, taking advantage of what may well have been the only dry period in the middle of winter. The rock is limestone, and there are a few short scrambles that are highly polished and very slippery. Every so often, Mallorcan outdoors folk roughen the really slippery bits by hammering the surface to allow boots to grip better.
I'm not advocating that anyone should hammer Sharp Edge, but in some parts of the world they just don't allow things to get into that state.