Snippet for Zendesk Help Center - permission for ticket submission based on user tag.

submission_permission.js

  var req_link = $('.submit-a-request');  // class selector for submit request link, now we can req_link.hide() and req_link.show()
  var sub_tag = 'tix_sub_approved';   //  sub_tag variable essentially holds the 'approved tag' value, whatever you decide
  var hc_user = HelpCenter.user;    //    Just a shortcut to type less later
  var user_path = window.location.pathname;   //  user's current path (everything after the tld, HC home pathname is "/hc/en-us/")
  var is_approved = false;
  
  if (hc_user.hasOwnProperty('tags')) {   //  anonymous user objects don't have a 'tags' property, first check if it exists...no? then no link
    if(hc_user.tags.indexOf(sub_tag) > -1) {
      req_link.show(); //  if tags[] exists and one of them matches approved tag, show link
      is_approved = true; //  since this is the only case where we approve a user, lets make a shortcut for future checking...
    }
  } else {   
    req_link.hide(); //  else just always hide the link.
  }
  
  if (user_path == "/hc/en-us/requests/new" && is_approved === false) {
    window.location.replace("/hc/en-us");  //  if you shouldn't be here, lets kick you out.
  }

This can be added to Zendesk HelpCenter to allow only users with a certain tag to submit tickets. Users without that tag will be kicked back to the home page if they somehow make it to the requests page. To use your own tag, simply change the value of var sub_tag = 'to_whatever_you_want';