I think I see an error in Google's javascript handle for Safari Clients:
if(b!=a)d.href= google.com/search?client=safari&rls=en&q=party+balloons&ie=UTF-8&oe=UTF-8&sei=c3 dOT973JtDlggeto_DBAg&gbv= +b};
maybeRedirectForGBV(document,location,"2");window.rwt=function(a,f,g,l,m,h,c,n,i ){return true};
---you can see on the first line where it says "party+balloons" , that was what I had typed in my browser search box in safari (located in the upper corner of the browser window).
basically what it is doing is comparing the contents of what is in the main google webpage search text box to the contents of what is in the browser searchbox. if they do not equal eachother then it redirects to whatever is in the browser text box.
here is the scenrio. you go to the google website. you search for "maps" and a bunch of results come up. you still want to keep looking, but this time you instead choose to search using Safari's Search box. Instead of looking up "maps" you decide to look up "Geography." it shows a lot of results for Geography.
You then decide to search again on the main Google Search box (on the webpage) for "Vacation."
Google compares the two searchboxs' contents "Vacation" to "Geography" . they don't match up...so Google decides that the Browser searchbox (which still contains the old search keyword "Geography") takes precedence over it's own main website's searchbox (which is very goofy) and redirects to the results for "Geography" instead of the new search "Vacation."
Because this javascript on Google is specified for only Safari Clients....this is why this doesn't happen when you search Google using Firefox. So, it's not Apple's fault.