Nothing yet, but that comes from an early start - I was on a rifle range starting around age ten, at a summer camp. It was there that I learned "never point a gun - loaded or not - at something you don't want to put a hole in", and "treat every gun as if it is loaded, all the time".
We have to pull the trigger on our XDs's to disassemble and clean, so hopefully we all VISUALLY INSPECT the firearm before that. I drop the mag (step 1); I rack the slide and catch the round before it can hit the ground (step 2). I put the round down, and set the slide on the catch (open), so I can visually inspect the chamber, rotate the gun so I can verify no mag, and in low-light I'll probe each with a fingertip quickly. Flip the lever, release the slide, point it at a wall (not out the window!), pull the trigger, and disassemble. Takes me about eight seconds to do it all, properly, and correctly.
Practice.
Practice.
Practice.
Use your EYES, and don't trust mechanical 'indicators' - always verify through direct contact with a round/empty chamber, or direct visual check of the round/chamber.
And don't EVER point a weapon at something you're not prepared to put a hole through, right then and there.
I actually carried my XDs the first couple of weeks, with a dummy round in the chamber - and checked it every single night to verify that nothing had "tripped" the trigger by dropping the mag, pointing it in a safe direction, and pulling the trigger. This is my first carry piece, and I was a little nervous at first about carrying "cocked and locked" so to speak. Now...it's 7+1 on my hip, every time, in my kydex IWB Alien holster.
Obviously, it had never tripped on its own.