Strict Layers Violated

It can always happen that a layer skips the one directly beneath it and accesses a layer further below instead, be it accidentally or on purpose. If layers that are basically strict are violated, their modifiability is affected. The number of a layer’s potential clients will increase, and the dependency between layers will grow.

Reference

M. Lippert, S. Roock, “Refactoring in Large Software Projects: Performing Complex Restructurings Successfully”. John Wiley and Sons, 2006.