I never let people use my cookies. I always start an anonymous window to let people use my browser (especially since most of the time, they'll want to check their email and go to gmail...).
Good for you. I bet majority of non-tech savvy people don't do this or even know how to do this
I guess - people have been seeing my previous search queries via chrome for years now. Isn't this what incognito windows are for?
Or anyone shoulder surfing (family, co-worker, etc) while you work on something together or look up movie times or anything will see contents of your gmail.
Just to reiterate: the box doesn't show any Gmail content by default. The default state of the box is collapsed. So we're only showing that you have matches in Gmail, and then you can choose whether to click and see the matches.