Vbulletin non-subscribed users if condition

i need to discuss on a code, as my old some topics contain that kind of event also, i have met a friend on internet who gives me that code,

<vb:if condition="$show['member']">
      <vb:if condition="$show['subscribed']">
      DO SOMETHING HERE
    </vb:if>
</vb:if>

this is the condition from bbcode can displayed to thread starter because thread started are automatically subscribed after creating topics, but i need a little change and modification in this, what should be change in the code for those are not subscribed to thread, i want to show message to users who are not subscribed to thread, and to be used on vb 4.2.3

Thanks...