The phrase panic button takes on a different meaning each time you ask someone what it means to them. For example, to the homeowner, a panic button signifies the use of an audible alarm, which is meant to scare away an attacking party. To a sales clerk, however, the phrase panic button means the invocation of a silent alarm, usually transmitted to police or central office personnel without the attacking party's knowledge.
In commercial applications, there are rules of the road that security dealers should follow. For example, you should always position a panic button where the public, as well as an attacking party, cannot easily discern its presence prior to or during a hold-up. The mounting location must also be such that the attacking party is unable to determine when an employee has intentionally activated it.