Can't say that I have. And from the topics I see around here not too many other people are forgetful either.;)
It's an interesting feature. But now I'm signed into G, and before I walk away for a break I'll have to sign out. What else prevents my mail and other potential personal information from being available to whomever should happen by if I don't sign out? I'm not all that thrilled with having to log in and out of something that has become such a convenient appliance. Most days I'll have multiple G tabs open - news, search. I prefer to log in and out of mail as needed. That means that essentially I'll be running logged out most of the time - and therefore unable to take advantage - even if I have promptly forgotten what I had found.