Is it illegal for someone to steal clan tags when they are not rightfully in the clan?
If so I'v got someone whos doing the exact thing to my clan
If its not illegal however there is no reason for me to upload the screenshot

Yes, that is against the rules. Next time you see this, make a screenshot and send it to an smod (blue names @ http://forum.toribash.com/showgroups.php )

I'v already made the screen shot
and have sent it to a mod
all I have to do is wait =]