It is possible to plan for common events. Rare events like a thread of particles that just happens to be in your path is hard to know without telescopes, probes and cosmology. If your coating is crystal, it is vulnerable along the axis where the crystal planes meet. Less than one degree of angle repeated impacts might break your armour. They used to over build bridges 3x before computer modelling, and apart from harmonic collapse they have stood well. I view discerning the probability of rare dense particle streams as preventing bridge collapses, as key even if the particle density is known.