As an NRA Instructor, I definitely believe in Safety first! I continually train myself and work on safety constantly.
I teach about 750 people annually at work, and get critiqued that we should shorten the course for those that have been through it already. The answer from my boss is always a resounding "NO". We go over safety, shooting fundamentals, and shooting positions and then the shooters get a range safety briefing again in the classroom, and another reminder at the range.
Safety, safety, safety...
I index so much, that I automatically index on the gun controller from my Playstation 3!