Looking at the assembled chain on my bike, it doesn't appear that wrapping safety wire around the outer plate and clip would accomplish much. The installed clip is narrower than the plate, so the wire wouldn't hold the clip "closed". And the wire could easily move toward a pin, where a sprocket tooth could hit it.
A problem I've had in recent years is assuring that a clip is truly seated in the pin grooves of a new master link. I don't know if it's true of all X-ring and O-ring chains, but the last new X-ring master link I installed (Japanese 520 X-ring chain) had a press fit of the plate onto the pins. I had to make a pressing fixture- piece of 1/4" aluminum with two clearance holes for the pins- to place over the plate, then use a C-clamp to press the plate fully in place. Even then, there was no "wiggle room" for the cliip- it had to be tightly against the plate to seat in its grooves. This was in ideal working conditions- comfortable shop, no time constraints, etc.