In both cases they saw lower rankings in new Y! than in INK, and at least one felt his site was actually better optimized for Y! than G, where he does really well, so in the absence of anything else, I guess he was grasping a bit.
No matter, I don't buy it anyway...but there is a fierce battle brewing, so I just wanted to check in and hear any recent notes of caution before moving forward with Adsense. (Personally I think the SE's would be crazy to start doing this to each other...deadly spiral, etc.)