~ $ cat /usr/share/polkit-1/actions/org.freedesktop.DisplayManager.AccountsService.policy 
<?xml version="1.0" encoding="UTF-8"?>
<policyconfig>
        <action id="org.freedesktop.DisplayManager.AccountsService.ModifyOwn">
                <description>Set properties of own user</description>
                <message>Authentication is required to set one's own greeter properties.</message>
                <defaults>
                        <allow_any>yes</allow_any>
                        <allow_inactive>yes</allow_inactive>
                        <allow_active>yes</allow_active>
                </defaults>
        </action>

        <action id="org.freedesktop.DisplayManager.AccountsService.ReadAny">
                <description>Set properties of any user</description>
                <message>Authentication is required to get another user's greeter properties.</message>
                <defaults>
                        <allow_any>yes</allow_any>
                        <allow_inactive>yes</allow_inactive>
                        <allow_active>yes</allow_active>
                </defaults>
        </action>

        <action id="org.freedesktop.DisplayManager.AccountsService.ModifyAny">
                <description>Set properties of any user</description>
                <message>Authentication is required to set another user's greeter properties.</message>
                <defaults>
                        <allow_any>no</allow_any>
                        <allow_inactive>no</allow_inactive>
                        <allow_active>no</allow_active>
                </defaults>
        </action>
</policyconfig>