I've seen this, and I do believe it, but it leads to a question: All those pictures of commercial beautiful shiny copper kettles, especially in Germany, but also Anchor Steam and others. Do they line them with something to prevent the Fenton reactions? Or is it a volume thing? Or are they doing something else to prevent problems?
I don't know the answers to your questions.
Some of this effect depends on how quickly beer is consumed--sort of like the best way to enjoy an IPA is to enjoy it fresh, as the hop aroma/flavors will diminish with time.
What I called staling compounds are oxidizing compounds, and so I'd presume the same effect is there as if you oxygenated fermented beer. There's an anecdotal report of one guy who did an IPA using LODO techniques, kegged in two 5-gallon kegs. One he had months after brewing, and it was (he said) just as good as the first one, no degradation.
There are ways to mitigate the effects--using things like Brewtan-B, for instance. Maybe that's part of their processes, but that's just a supposition.
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As an aside, I've always thought Anchor Steam had something "off" about its flavor. I brew a California Common I think is much superior to AS. Might just be my palate, but now that I think about it, I wonder how much of what I perceive in AS is oxidation. I have a bottle of AS in my fridge; going to have to try that and see.
In some contexts, certain flavors--oxidation, perhaps--might be seen as emblematic of the style. Sort of like how fermenting warm works for Saisons because the yeast expresses flavors at that temp that would be inappropriate in another beer.