tedster - 8:44 pm on Feb 26, 2013 (gmt 0)

this loss would seem unlikely to trigger an anti-spam algo, although I suppose it's possible

From what I've seen, multiple, chained 301s are more likely to trigger a manual check. However, I have heard Matt Cutts talk about an automated rule for certain types of 301 chains. In fact, the rule was informally named for a relatively well known early SEO who was leveraging the possibilities of 301 chains in a clever way.