[OpenID] Logout Use Case

[SitG Admin]

>I don't understand how you can use an OP to log into an RP without 
>the OP being aware that it's sending that assertion.

Sure. But if you're using OP1 *and* OP2 to login at RP3 (say, via 
MultiAuth), then the user should be able to keep OP1 and OP2 unaware 
of each other; so, when RP4 (which only knows the user through OP1) 
tells the user to logout from all of OP1's sessions, it can only send 
the user to OP1; will OP1 also send the user to all the RP's it 
knows, just in case any of them is currently using MultiAuth with the 
user?

-Shade