Comment 23 for bug 857651

I think global exclusion option is needed. Imagine a big domain environment where there are about 20 admins. And all these admins are policykit admins. Once you try to use policykit somehow, all these admin accounts will appear in the panel, but I don't really need them there. The same for login screen - if you are admin, then I think you know how to type your account name. The same time a typical user shouldn't see this trash of unknown strange account names.

Or another way is to implement some cache setting (suggested my Matthew Monaco). If cache is set to 1, then only the last logged user is shown.

The best of course is to implement both of these features.
Thanks.