Neil Keating ( Talkback, September 22) is very wrong about the origin of “pulling the pin”. It has nothing to do with hand grenades.
The saying dates from the middle of the 19th century, and to “pull the pin” was to separate two railway cars that were connected by the infamously dangerous link-and-pin couplers then in use in the US.
Soon, disengaging from a situation or relationship was also referred to as “pulling the pin” in wider society. A cliché, maybe, but exactly apt in the context of the Morning Report story.