I remember a rather counterproductive result on the Beaurofighter, when the government agency (NEFMA?) imposed per-gramme penalties on sub-system manufactures for providing overweight bits.
The consequence was that all the companies did a cost-benefit analysis, and decided it was cheaper to take the hit than do all the work to lighten everything down to spec.
Still, I suppose it shaved a few quid off the bill, but that wasn't really the point.
G