As a rescuer of exotic animals, I feel trust in my vet is VERY important!  Owners should ALWAYS be notified if a student will be present and if that student will be doing any proceedures on their animal.  I have no problem with vet students being present with my vet, at any year of practice.  Students at any level are welcome to meet my animals and - IF NOT ILL - handle them under guidance to learn how to check vitals, palpate, check teeth, clip nails, and other NON critical procedures.  However, I think only students that have at least 2 years of training should do any more advanced procedures, and ONLY while closely supervised!