There are places that prohibit people from entering with objects that may be used as weapons . Most public schools in North America do not allow their students to bring pocket knives , butter knives or chain-wallets , sometimes with harsh zero tolerance policies . Airports typically prohibit objects that could be used as weapons from being carried , as a carry-on or in a carry-on bag into the aircraft cabin . The security repercussions after the September 11 attacks saw restrictions widely extended to cover even objects like nail clippers and spiked wristbands , A makeshift weapon is an everyday object that has been physically altered to enhance its potential as a weapon . It can also be used to refer to common classes of weapons such as guns , knives , and bombs made from commonly available items
September 11 attacks
September 11 attacks
Improvised weapon