There are stories going back decades about compromises in manufacture.
The one I like was told of Lockheed Constellation manufacture. A KLM rep gigged a mis-driven 1/8" flush rivet in a skin panel, and insisted it be drilled out. The assembler knew that this would result in an oversize hole, requiring (per KLM spec) that the skin panel be replaced.
But Lockheed had their own rivet shop, and they made (under the table) 5/32" rivets with the same head profile as a 1/8" rivet. Indistinguishable from its 1/8" neighbors, once driven!
Problem solved. Of course there was no structural issue here, merely a visual one.
