driller41 - 10:04 am on Apr 24, 2013 (gmt 0)
In my experience it is oncoming links of poor quality/unrelated sites that is kicking off the demotions.
Most of my EMDs have been torched, the ones I built links to from the usual rubbish places - web2.0, bookmarks ect are gone, age did not help, a couple if sites I left alone are still there and ranking/making money - google must hate me for this :)
As to the 301 redirect - I thought it was established that the new site will rank for a few weeks then the penalty catches up with it and it is demoted - again I found this to be the case from my tests.
My best result with a demoted site was to register a new domain name and move the whole thing across without a redirect - the new site is still ranking.