Part of successful development teams is to build within the newest and least experienced members an insane FEAR of failing so that it drives them to build better things rather than be casual about what they do and release garbage. Too many young developers today are growing up with the mentality that they can be casual about their work. That mistakes don't matter. That getting it right isn't the most important thing. That's because they have massive support systems built around them with people who actually answer for when things go wrong, when these young naive developers release crap, break things, and these same people also FIX the crap and garbage that gets released, all because of naive programming.
So, please tell EVERY developer that a version control mistake is grounds for termination and you'll make sure that they REALLY dedicate time and attention to their work.