Obvious ways to catch me out:
* Hand me an unsafe piece of equipment.
* Hand me a piece of equipment which, when twiddled to either extreme, drops off.
In other news, I took the lid off something marked "Do not remove lid, honest". Dave expressed that he had been waiting for some time for me to do so, and was not surprised to catch me in the act. The piece of equipment in question no longer rattles. I haven't plugged it in to see if it still works. Perhaps I should let Dave do that.