Forgive me if this has been raised before; I haven't seen any direct discussion of this issue.
On the SiteAdvisor site results page, there is no indication of when a site was last tested. I know (from the icons that appear next to sites on Google search results) that some sites are subject to frequent testing - the Secure Sites. Most sites, though, appear to be tested only once, and the test results then determine the site's safety rating until or unless there is a push to modify the rating (see theSiteReviewer Central page for a list of sites currently under review).
This may not be a problem if a site's testing was carried out recently, but could be a problem if the site's behaviour has changed since it was tested. Others have noted this fact in passing, in board discussions and site reviews, but no-one apparently has been sufficiently concerned to ask for a change. Would it be difficult for McAfee to modify the testing procedure so as to put the date of testing onto the results page?