On looking at a page of Google listings, I could see no trace of the safe search icons that Site Advisor (version 6261) displays and the icons possessed no mouseover behaviour although the links were available for clicking.
The browser is Firefox 3.0.1. I have now checked the setting 'Highlight search result links' and unchecked 'Display safe search icons'.
This rather contradicts my enthusiasm for version 6261 as compared with the derided 2.8.255. However, 6261 still does the important stuff without reducing the client area and, since my colour vision is OK, highlighting search result links makes it less likely that I will enter a red or yellow site.