Well... yeah. And that's easy to say from behind a keyboard. But out in the real world it isn't that easy. What is a "reminder"? How do the reminders remain effective? The reminders themselves become ineffective, because they follow a pattern over time. You can't just have someone jump out of the bushes and attack a guy once a month and scream in his face, "The weapon you are carrying is dangerous! Treat it with respect!" The same is true for truck drivers, or heavy equipment operators, or race car mechanics, or lab technicians that work with lasers, etc, etc, etc. There are a lot of dangerous things in our lives, but even the dangerous stuff gets boring if you work with it long enough. Mindfulness is hard to maintain over the long term. Because we are humans, and we fall into patterns. Casualness comes with lack of reminders.