In my opinion - Google will HAVE to do some re-indexing because there are thousands of sites that have had legitimate, fresh data and pages dropped to the Supple
MENTAL Club due to their infrastructure problems with Big Daddy.
After much comparison and analysis with other site owners/
SEO's, a common denominator is duplicate content.
Sites that have dynamically generated data that did not address things as simple as assignment of unique Title Tags seemed to have triggered supplemental status under the "duplicate data" umbrella even though the content was unique and fresh / valid.