What if the protection system is compromised? You cannot possibly test for all the damage that might be done to a product and its corrosion consequences. But you can model it damaged any way you want. Modeling is an integral part of understanding how damage to coatings affects corrosion protection, and whether a protection system is sufficiently robust for use in the real world, as against testing. It is one thing to test an undamaged coating in a B117 cabinet, but an entirely different thing to understand what will happen if the protective system is compromised or missing. Modeling allows us to test how robust the system is after it is damaged in any one of the many ways that can happen in real life.