Earlier quoted context omitted.
If this isn't enough to convince you, nothing will be. I'm not sure how the evidence could be any more convincing. Content from Google's result database ends up used to generate Bing's results, full stop. Proved. It may be technical error, it may be only used a little bit, it may be deliberate, it may be accidental and perfectly ethical by some people's standards, there's all kinds of ways to legitimately interpret t…
"... we thought this practice was happening for lots and lots of different queries, not simply rare queries ..." My comment was in reference to that.
I hate to be a bit harsh, but that argument sounds more like spin or rationalization than a logical argument. It sounds nice but it doesn't make sense if you try to actually map it back to the real world, where somebody had to type real code to produce the effect you're hypothesizing, and they weren't writing this code with this debate in mind in advance.