try this, I am not entirely sure if it will work but change
Code:
if (is_user_admin(id) && (!equal(name, "[ADMIN]", 7)))
to
Code:
if (is_user_admin(id) && (!equal(name, "{GK}", 4)))
Im going to take a wild guess here and figure that you didnt change the number after the admin tag, that is why it kept changing because the number stands for the number of characters the plugin checks for the equal to return true, hopefully that will work.