Sell baggage space on airlines?

I posted this as a problem in the “Ideaspace” platform here.

I usually end up paying for 30KG baggage + 10KG cabin when all I carry is <8KG in my flight. Can I just sell the other 32KG and get back portion of my ticket cost? Will the airline buy this back? Can there be a middle man who will do this on both our behalves? This, as I note on the platform, is a regulatory nightmare. God knows what can be pushed into such sold baggage space that would then compromise the security of the flight, its passengers or the destination country (at least its airport). With rising security issues all over the world, a new venture trying to add more nightmare is the last thing to have. But maybe it needn’t be a nightmare after all. Just maybe.