I often hand my laptop or iPad to my wife so that she can look at something/use it for a few minutes while sat on the sofa (her computer is a desktop in the other room).
I normally don't bother logging out of whatever sites I'm logged in to.
I'm not too bothered what she sees if she opens up the Facebook tab with me logged in - but I can see that it may be a problem for some.
And I don't think that "hand it over for five minutes to check something" is that uncommon a use-case.
"here - look at this interesting article on Wikipedia"
... she starts reading ...
... I get bored and go to make cup of tea, forgetting that I hadn't logged out of Facebook ...
... she finishes article, closes tab and finds herself on my Facebook page ...
It is my fault, but a "clear history" (or at least make my history invisible) function would mean that mistakes like the above will have much less impact
I normally don't bother logging out of whatever sites I'm logged in to.
I'm not too bothered what she sees if she opens up the Facebook tab with me logged in - but I can see that it may be a problem for some.
And I don't think that "hand it over for five minutes to check something" is that uncommon a use-case.