Redirect instead of Access Denied

Is there any case where a logged in user attempting to access /user/login/sso (regardless of reason, you can't control what users decide to bookmark or link to) should get "Access Denied" instead of at least redirected to / or something?

1. Request for /user/login/sso should redirect to some default setting if user is already logged in.
2. Request for /user/login/sso?destination=node/123 should redirect to node/123 after auth or immediately if logged in.

I know I could use r4032login module to redirect on Access Denied, but that won't take into account "destination" so it's half a fix for an issue that shouldn't exist IMHO.