martinibuster - 6:10 pm on Feb 29, 2012 (gmt 0)
That would support the 301 theory
301 redirects are depreciated already, so that they pass a reduced amount of PageRank. Web publishers change internal URLs during upgrades of technology or updating their pages to new versions. If the 301 redirect is no longer sending PageRank then that will mean a website has a disincentive to upgrade their technology or update their web pages.
I agree with what Whitey suggested, "Something of low relevance that causes conflict with those objectives, and is done in an easier manner." Does the 301 theory qualify as a low relevance signal?
One also has to wonder what was behing the depreciating PR of 301's in the first place.