You guys are absolutely correct, and I was certainly less than clear. I did not mean to use shorting to trip breakers, but just as a last assurance that the circuit is dead.
When I am about to handle wiring on a circuit I have locked out, or otherwise "should" be dead, I still touch each hot wire to ground or neutral before handling the bare ends.
I mentioned "As long as you're replacing the old receptacles anyway..." because the arc will discolor the receptacle when you discover the hard way you missed a breaker.
