Haven't any of you ever had your one control hand bounced off the handlebars when you were drinking or eating? You have maybe a moment where you dive a bit and think, well, I might be going down. Except you don't, because your wheels are still under you and you're in your saddle.

Breaking a stem isn't necessarily the end of the world if you're comfortable on your bike. Your wheels are still rolling along and keeping you up and you've got working brake levers right there if you didn't panic and drop the bars.

Plus, I bet that won't fatally damage the stem. Especially if your handlebars are near or above your saddle. It's hardly even under much stress in a lot of riding positions. If you're worried, epoxy the screw in. That should ease the fear of stress risers.