Great thread Pete!
One thing that was said to me years ago was actually about power tools, but I apply it anywhere that I am doing anything where I can get hurt.
"The minute you get comfortable with a tool, put it down and walk away! You have now entered the area of making a mistake that can and almost certainly will hurt you!"
I feel the same goes for the dunes, and many other things for that matter. Once you become comfortable with danger, you start letting certain things slide and not paying full attention, that's when accidents happen.