They can setup and bond before the water and water pressure builds to unacceptable levels under the fresh coating. This includes many kinds of plastic surfaces. Oily surfaces can be tricky, Just feeling the surface is often not good enough. Hosing down, high pressure water, and even grit blasting, is no guaranty that greases will be removed, indeed, they will probably stay behind. Greasy, oily surfaces require a degreasing chemical to remove the film.
Experts suggest washing down the surfaces using a degreaser and stiff brush.
It is wise to make this a standing surface preparation step, wiser still to do at least two degreasing wash-downs. Unfortunately, even simple degreasing or more advanced hot steam and chemical systems may not work completely. The author has seen floor coating samples collected from peeling floors that were dirtier on their underside than on their top surface. The coatings stuck, but to the dust and dirt on the floor instead of to the floor itself. Hosing down the surface to remove the loose materials works somewhat, but also leaves a lot behind.