Both of these threads are just odd to me, because I am completely paranoid about not having enough food when hosting, so I usually prepare about 25-50% more of everything than we end up needing. So, a person taking twice his share of the cheese wouldn't affect anything at all.
I realize that's not always possible due to finances, but I do think it's a little odd when hosting (especially buffet or make-your-own style) to provide exactly enough for everyone to have X meal, configured exactly as planned, without any room for deviation. I see all the time on here, people have said that they couldn't eat a main course so they filled up on salad and bread. If there was just enough for each person to have X amount, that would mean they'd be shorting the other diners of salad and bread.
If that is the case, then I think it is rude to take more than your X share of anything, whether it's meat, cheese, lettuce, mayo, ice..
I do think this is a good point. I don't have much experience hosting; but it seems to me like it would be difficult to properly estimate how much food one should have. I'm sure I would err on the side of massive overkill if I could, which would then result in other problems behind the scenes (money, storage, leftovers going bad before I could eat them, etc.).
I remember I started a thread a couple of years ago about how much pizza to get for my office--I had estimated two slices per person, because that's what *I* ate, and ended up short because people took more, and my boss added extra people at the last minute. The responses I got to the thread were really varied in how much pizza was "typically" eaten by someone. So the next time, I bought pizzas estimating three slices per person, and--due to various different circumstances from the first lunch--I had massive leftovers! Which I was afraid would look to my boss like I was being careless and wasteful, since she was paying.
So maybe it just takes some people a few tries to get the balance right, of how much food to provide. And, they're bringing their own expectations to it--oh, I don't really like olives, so I'll just get a tiny jar of them, it's not really a big part of the meal--and it turns out most of their guests love olives and consider them essential to their meal, so they run out. The guy in the sandwich party story, for example, obviously preferred meat way more than cheese and assumed his guests did, too (because no one had told him one person was a vegetarian).
And then on top of that, you occasionally have the super-greedy guest who takes substantially more than they should, or at least before they should--like my co-worker who flat-out announced she was going to be "a greedy piggy" and got a second large slice from a small cake, before everyone had even had their first