To limit the probability of cutouts that coincide with those of the top layer of shingles, which could lead to less than the required 2 thicknesses of shingle over the entire roof, which could lead to insufficient protection of roof decking or sheathing from moisture absorption, ultraviolet radiation, and freeze-thaw cycling, which could lead to premature failure, which could lead to water penetrating directly to roof decking or sheathing, which could lead to precipitation or meltwater ingress, which could lead to deterioration, which could lead to the structural failure of roofs or walls or of assemblies protected by roofs or walls, which could lead to harm to persons.