No single-sign-out notifications issued on re log-in

[vemv]

When one presented with the screen:

You are currently logged in as 'foo'. If this is not you, please log in below. 

And one proceeds to log in (instead of visiting /logout first), no single single-sign-out notifications seem to be issued.

[vemv]

Note that this represents a severe issue - the newly-logged-in user may now have access to applications he doesn't have authentication rights for.