[faithless]

Same thing happen to me as well.

First I took some napkin to stuffs the hole where the hammer would rest in the slide.

Then, I took a box cutter, snapped a piece of the blade off. Tape this piece of blade to the bottom of the slide, so the hammer will have no place to rest, but stay in cocked condition.

Last, ask your significant half to use permanent marker, and write on your forehead that "I will always test the lower receiver before putting the slide back in place again."

Hope my broken english helps you.