How to hide the xtd buttons from the ticket message area?

Besides disabling them from the Plugin manager area you could try hiding them on the RSTickets!Pro submission page. In order to achieve this you just need to edit the default.php file from components/com_rsticketspro/views/submit/tmpl/ and just before the last </script> tag add something similar to:

    window.addEvent('domready', function(){ document.getElementById('editor-xtd-buttons').style.display="none"; });