thanks for the responses

I've added attempted Nathan's suggestion - I've added a true/false field on the sc_cat_item table called "u_show_message"

I've adjusted this section of the server script of the widget but I think I'm "including it in the catalog item object" incorrectly...

 data.sc_cat_item = $sp.getCatalogItem(data.sys_id, true);
 if (data.sc_cat_item.category) {
  var categoryGR = new GlideRecord('sc_category');
  categoryGR.get(data.sc_cat_item.category);
  data.category = {
   name: categoryGR.getDisplayValue('title'),
   url: '?id=sc_category&sys_id=' + categoryGR.sys_id
  }
 }
 
 data.hideMessages = data.sc_cat_item.u_show_message;

and in the client controller I've wrapped the sp_util like so

 if (data.hideMessages == false) {
   spUtil.addInfoMessage(t);
  }

I've tried === and == just in case (I know elsewhere on the platform true/false evaluate unexpectedly...

submissions submit and generate REQ/RITMS properly but the "submitting" never resolves