To disable the permissions checking where you see
AUTHENTICATING FOR org.freedesktop.udisks2.filesystem-mount-other-seat
edit /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy and look for
<action id="org.freedesktop.udisks2.filesystem-unmount-others">
<defaults>
      <allow_any>auth_admin</allow_any>
      <allow_inactive>auth_admin</allow_inactive>
      <allow_active>auth_admin_keep</allow_active>
</defaults>
and similar, and change auth_admin and auth_admin_keep to yes.