Ethics of Waste

This is not a question about sustainability, those tend to be easy from the moral side of the house. Yes, we should reduce consumption, reduce toxic emissions, be more efficient, and live within our ecological means. My question is about one's ethical requirements when it is clear that all other things being equal, something is going to go to waste. Waste seems inherently morally undesirable, but does that mean that avoiding waste gets figured into the ethical deliberation?

You are at a ballgame and have purchased an upper reserved ticket. Your team has had a lousy year and there are LOTS of better seats open and they are not going to be filled. Is there anything wrong with moving down? On the one hand, you are taking something you didn't pay for...That's stealing. On the other hand, it is not a scarce resource. That better seat would go unfilled if not for your butt. Why should you enjoy the game less when you could enjoy it more and hurt no one in the process? Is it a moral insult to the people around you who did pay more for that seat? The idea is that it is unfair for them to have to shell out extra money and get less in return. They played by the rules, why should they get penalized by paying more for the same thing? The response, I suppose, is that what they paid more for was seat insurance, the guarantee that the seat would be theirs. If a lot of people showed up for the game, they'd still be there but you'd be SOL. Is there a difference between sneaking into better seats and sneaking into the stadium without paying at all if the game is not sold out? Does the fact that the seat would otherwise be wasted turn what would normally be wrong into something morally allowable?

Similarly, if you are a vegetarian for ethical reasons, believing it is wrong to kill an animal for the sake of eating it and you see cooked meat that is going to be thrown away, would it be problematic to eat it? There is no individual animal in the world that otherwise wouldn't have been killed and isn't it more of an insult to the animal that it be killed and wasted, than at least someone getting some sustenance from it? Is the fact that something would otherwise go to waste morally relevant? Does it come in as a factor in the circumstances?

Along these same lines, what of the Christian slogan, "Jesus died for your sins." If that was true and we all stopped sinning, then he died for nothing. It would trivialize the sacrifice. On the other hand, if it is true, then the more we sin, the more Jesus will have died for, the more meaningful the act will have been. Does that mean that a good Christian ought to maximize sin out of respect? Surely not, but why not?

Is waste intrinsically wrong?