I legitimately had my players pull that one on me once. Door into a secret lab disguised as a closet was beyond their skill, warded by powerful magic, etc etc. They looked at the floor plan and saw that the closet protruded from the main wall a bit. “Why not go in through the side?” I hadn’t thought about it. I figured the villain hadn’t thought about it either. A simple pickax later and they were in.
Door was impenetrable but they cheaped out on the walls.
I legitimately had my players pull that one on me once. Door into a secret lab disguised as a closet was beyond their skill, warded by powerful magic, etc etc. They looked at the floor plan and saw that the closet protruded from the main wall a bit. “Why not go in through the side?” I hadn’t thought about it. I figured the villain hadn’t thought about it either. A simple pickax later and they were in.