I do a lot of work with a large university that has "optional" sustainability requirements. This is frustrating for contractors - what happens if they miss, say, 75% construction waste diversion? At the same time, an Owner wants to know the Contractor will perform the actions that result in a LEED rating.
Of course we can say "Contractor SHALL do this and that" in the specs. But have you worked on a project where there were teeth in the LEED specs - what if the contractor misses a construction waste diversion threshold, or brings a jug of high VOC paint onto the job - have you built penalties into the specifications to help incentivize the Contractor? What specifically have you done on your projects?