1. A citizen carries a multitude of ID cards, which can be for various purposes and issued by multiple agencies.
    
2. For example a single adult bonafide citizen may have a social security card, national ID card, a passport, a voter card, a driving license, etc.
   

1. There are multiple numbers of print cartriges that will fit a single model of a printer. 
    
2. Similarly the same printer cartridge may fit into multiple models of printers.
    
3. There is no easy way to determine which printer cartrige can be used where.This is true for all printers, inkjet or lasers.

The UK’s Royal Air Force has several squadrons of Sea Harrier “Jump Jets” fighter aircraft. These are known as Jump jets because they require very short take off and landing lengths on the runway.

1. No system to really locate a person, even within a vicinity of a few hundred feet.This is really a big problem in case of a fire or other Disaster.
    
2. One still has to carry out a physical head count.
    
3. Once given a badge, a person can freely access any part of a large site which is not desirable because of safety and security.