So I received a new watch yesterday, and as is my normal routine, after I adjusted the bracelet to fit, I checked every screw in the links for tightness. No problem.
Tonight, when I was in the kitchen, I dropped some stuff into the garbage compactor and ... felt something odd .. my new watch slithered across the back of my hand and into the garbage.
Luckily, the screw which had fallen out was resting nicely on top of a piece of paper. I had completely not noticed that the end links were held onto the watch head with ... ready? ... SCREWS.
If you think you tightened them all .. check again. Tighten them
ps - half of the caseback screws were loose too.