For the Basic Rider Course, we provide the bikes; Yamaha VStar 250 or Yamaha TW200 (for longer inseams).
Usually one or two get no kidding just 'dropped' each class. About every 5th class of 12, someone will try and defy physics by using the front brake to correct their speed while IN the turn and wipe out.
For the BRC2, Experienced Rider Course, and the Advanced Rider Course, the students bring their own bikes, and very seldom does one get dropped, but it does happen - usually if the student had less than 6 months 'good' experience on that particular bike.
Hope that answers your question....