Munnyspinner, whilst I applaud you for trying to state your case in this debate, that is where my admiration for your behaviour ends.
I am the quiet, law-abiding (larger) customer that pays for my ticket, boards the aircraft when called, avoids asking for extra service as the CC have enough work to do, never put my seat back unless the seat behind is empty, takes whatever seat is assigned to me, and send compliments to the airline should the service warrant it. I'm not a martyr, just getting from point A to point B as quickly and efficiently as possible. Petty things like an extra degree of seat pitch just aren't worth the effect on my conscience.
If there are other people on the flight like you, then the CC have to spend precious pre-takeoff time dealing with the issue of who gets which seat, delaying me and my fellow pax. It's not about revenue, theft, or misappropriation, just 'doing what is right'.
I believe that given that the anti-terror 'air police' presence and/or requirements, that there should be an additional crew member on all 100+ pax flights dressed as a security guard (without a firearm). For selfish idiots that try jumping classes or Y class louts drinking everyone elses share of beverage, their name is taken, they are escorted back to their assigned seat, and a note made in the airlines loyalty system so that next time they fly, check-in crew can be on the lookout for them.
If I had paid US$5k for a business class seat, and Joe Economy slides in next to me on his US$1k Y class fare, I'd sure be upset with the airline that he be allowed to get away with it...
My 2c.