What Does Molly-Guard Mean?

A molly-guard is a physical shield or barrier that prevents unauthorized or improper access to part of a hardware device. The molly-guard is placed over a button, lever or other control so that less experienced users have more trouble getting to it and it cannot be activated by accident.

Techopedia Explains Molly-Guard

In the urban legends surrounding this term, “molly-guard” is often attributed to a programmer working on an IBM 4341 mainframe computer. According to the story, the programmer’s young daughter, who was named Molly, pushed a particularly important control button twice during a given day. Presumably, the programmer then constructed some type of molly-guard to prevent further difficulty.