Trainer is low stress!!??? Que???
Being a trainer is a very stressful job. Between the travel, being the punching bag, and generally having to have all the answers, regardless of how esoteric the question, means that training is a VERY stressful job.
Not only that, but as a trainer you encounter ALL of the problems you say we don't. We have to explain WHY the users system crashed or why certain things are happening in the customer's environment. We also have to deal with project timelines and fully understand where the project is and what has been done...not only that we have to completely understand the customer's environment and what has been done to it.