One other detail: the survey is sent to all attendees who checked into at least one session, but the results are aggregated by student and volunteer responses. The survey is not anonymous, since we're associating it with your account in the db, but we don't show the survey-taker's name anywhere in the UI with their response.
(If you wanted to get separate feedback about a teacher training from the workshop, this is a place where it seems like having an entirely separate event for the teacher training would be easier to handle than having it as one session of the whole event.)