Those awful tamper proof stickers on the sides of the case where it presses together would work.
If a drop happened and chipped a case, the likely hood of case separation wouldn't be all that likely, or not enough to make the tamper proof stickers separate
Sure you wouldn't be able to open the sides to remove newton rings, but one on each side in the middle where the case presses together anyway would work. If the sticker shows ware an automatic regrading needed.
Simple and effective, but idk, just a thought