The use of a safety button is a well known means of providing tamper evidence. However, one of the concerns with the button feature is the ability of one to overcome it. For example, a vacuum packed container closed by a closure provided with a safety button may be opened, the product tampered with, and the closure reapplied under vacuum conditions. In such event, the button will be in its downwardly drawn position and will fail to give evidence that the container has been opened.
Another deficiency of closures provided solely with safety buttons is that frequently users do not note the condition of the safety button.