incrediBILL - 4:57 pm on Aug 23, 2010 (gmt 0)
webmaster input that in the absence of cloaking equally affects the human visitor and SE crawler.
the canonical tag, however is meta information that for practical purposes is intended only for search engines.
That has nothing to do with my point which was webmasters can make canonical mistakes more than one way, including but not limited to mistakes in 301 redirects, meta canonical, internal link, inbound links, etc.
You must have consistency throughout or it just compounds the problem and doesn't alleviate it.